Uranium-238 decays very slowly with a half life of 4.5 billion years. what percentage of a sample of uranium-238 would remain after 13.5 billion years?
The mass of Uranium halves every 4.5 billion years, so 13.5 billion years= 3 half-lives.
[tex]M=M_{0}[/tex] × [tex](\frac{1}{2} )^n[/tex]
Is the equation that describes the decay, where [tex]M^0[/tex] is the initial mass and [tex]n[/tex] is the number of half-lives passed.
So if 3 half-lives have passed:
[tex]M=M_{0}[/tex] × [tex](\frac{1}{2} )^3[/tex]
[tex]M=M_{0}[/tex] × [tex](\frac{1}{8} )[/tex]
[tex]M= \frac{1}{8} M_{0}[/tex]
So there will be 1/8 of the original mass left after 13.5 billion years, or 12.5% of the mass left.
Number of chromosomes in daughter cells in mitosis.
Answer:
46 chromosomes.
Explanation:
In mitosis, two daughter cells separate from the parent cell, which has 46 chromosomes. In the prophase, the parent cell duplicates its own chromosomes to create two identical cells.
Each daughter cell should have the same number of chromosomes as the parent.
Answer:
The cell will possess an identical and full set of 46 chromosomes, or 23 pairs of homologous chromosomes.
which statement best describes a pattern of reproduction exhibited by most aquatic vertebrates
Aquatic organisms have external fertilization and reproduction is done through mating of male and female.
How do aquatic vertebrates reproduce?All vertebrates reproduce through mating of male and female. Aquatic species generally have external fertilization, whereas terrestrial species usually have internal fertilization.
In conclusion, aquatic organisms have external fertilization and reproduce through mating of male and female.
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Thomas was interested in how the disruption of rock layers can be used to find a rock’s age. Which of the following are examples of how rock layers may be disturbed or changed? Choose the three that apply.
Answer:
igneous intrusion, extrusion, faults
Explanation:
Folding, tilting, faults, igneous intrusion, extrusion, and unconformities all disturb rock layers
britannica quiziz
List some advantages the shark has due to the ability to maintain warmth
Answer:
go to the colder parts of the ocean
Explanation:
write about life span in details
Answer:
Life Span;The the period between birth and natural death of an organism is called life span.Life span varies from less than one day to more than 4000 years. Life span are not related to size or complexity of the organisms.Crows and parrots are of equal size. Crow has a life span of only 15 years while parrot lives for about 140 years.Similarly, Mango tree lives for about 200 years while Peeepal (Ficus religiosa) has a life span of about 2500 years.Banyan tree (Ficus bengalensis) spreads over a very large area but does not live beyond 500 years.
-TheUnknownScientist 72
1. What organism is essential for the nitrogen cycle to continue?
What does the bacterium use to move?
Answer:
Many bacteria move using a structure called a flagellum. Explanation:
In roots the _____ forces water and solutes to pass through the plasma membranes of _____ cells before entering the _____.
welp-..
11. What are some of the characteristics of Alkali Metals?___________________________________________
_______________________________________________________________________________________
12. Which group is inert or non-reactive? ________________________________________________________
13. Which group is known as Alkaline Earth Metals? ________________________________________________
14. What are some characteristics of Group 2? _____________________________________________________
________________________________________________________________________________________
15. What is group 17 known as? _________________________________________________________________
16. What are some characteristics of Group 17? _____________________________________________________
_________________________________________________________________________________________
17. What name is given to group 18? ___________________________________________________________________
18. What are some properties of group 18? ______________________________________________________________
19. What happens to an atom’s mass as you move from left to right on the periodic table? ____________________________________
20. As you move from left to right across a row of elements in the periodic table what happens to the number of protons and neutrons? ______________________________________________
1 18
2 26
3 7
4 same number of electrons
5 Si Te Sb B Ge Po As
6 metalloids
7 Shiny, brittle, solids, good electrical conductors
8 group1 except for hydrogen
9 lustrous, malleable, ductile, good conductors of heat and electricity
10Alkali metals
11 High reactive metals.
Not found freely in nature.
Stored in a mineral oil solution.
Low melting points.
12 noble gases
13 Group 2A
14 have two valence electrons or the electrons furthest from the nucleus,
15 Halogen
16 Melting and Boiling Points (increases down the group)
Atomic Radius (increases down the group)
Ionization Energy (decreases down the group)
Electronegativity (decreases down the group)
17 noble gases
18Noble gases are colorless, odorless, tasteless, and nonflammable gases under standard conditions.
In the periodic table, the noble gases are arranged according to their boiling point.
19 are adding more protons and neutrons to the nuclei.
20 left of the staircase created by B, SI Ge, As, Sb, Te (metalloids), are all metals right are non-metals. Next the atomic number and therefore the proton number increase as you move from left to right B - 5, C - 6, N -7.
Help me please!!! Can somebody help me
C, the third option
the other two don't make sense at all and C is correct
The coefficient of viscosity of blood is directly proportional to the frequency of interactions of erythrocytes with the vessel walls. As blood enters small vessels, many erythrocytes tend to flow in the center of the vessel. Given this information, which graphic best describes the effect of vessel diameter on the coefficient of viscosity?.
The coefficient viscosity is the resistance for blood to flow. There is a direct relationship between vessels diametre and viscosity. In the attached files it is the graph that best describes this relationship.
What is blood viscosity?
Viscosity is the property of fluids to resist the tangential displacement of molecule layers.
Blood viscosity refers to the resistance for blood to flow. Blood viscosity depends on the blood density and the vessel diameter.
Viscosity increases when the number of blood cells increases and when more cells get in contact with vessels walls.The more viscose is in the blood, the greater resistance there is to move it, and the more blood pressure it requires to flow through vessels.
Viscosity decreases when blood velocity increases.According to this framework and to the problem statement, we could assume that
smaller vessels ⇒ faster flow ⇒ less wall resistance → less vistositybigger vessels ⇒ slower flow ⇒ more wall resistance → more viscosity
In smaller vessels, blood flow is greater and more cells move in the center, leading to fewer cells interacting with walls. There is higher pressure and less resistance for blood to flow.
In bigger vessels, blood flow is slower, and more cells are interacting with each other and with the vessel walls. There is lower pressure and more resistance for blood to flow.
Since the coefficient of viscosity is directly proportional to the frequency of interactions of erythrocytes with the vessel walls, we can assume that blood flowing through bigger vessels express a higher coefficient of viscosity than blood flowing through smaller vessels.
In the attached files you will find an image representing the relationship between the coefficient of viscosity and vessel diameter.
You should compare this image with your images and choose the correct one.
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A group of scientists determines that a mitochondrial DNA sequence shared by two species has a constant mutation rate. The sequences of mitochondrial DNA for the two species are shown below. Species A: GACTGGGCATTA Species B: GACCGGACATTA Based on this information, which of the following best explains the difference in the DNA sequence between the two species? Species A and B probably share the most recent ancestor because they only differ by three mutations. Species A and B have fewer differences between DNA sequences means that fewer mutations occurred. Species A and B probably have distinct ancestors because they have many differences in mutations. Species A and B are closely related because they differ by five mutations in their DNA sequence.
Species A and B have fewer differences between DNA sequences means that fewer mutations occurred. It is likely due to sequence homo-logy.
Whta are mutations?A mutation is any alteration in the nucleotide (DNA) sequence of the genome of a particular organism.
The linear order of nucleotides and their differences (mutations) can be used to infer homo-logy between two species.
In this case, there are only two different nucleotides in these sequences, thereby sequence homo-logy indicates a likely common origin.
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Answer: Species A and B have fewer differences between DNA sequences means that fewer mutations occurred.
Explanation:
Took the test and got it right
Starch is too large to cross the selectively permeable membrane and must be broken down into simpler molecules
before it is transported to other cells. To do this, starch-digesting enzymes called amylases are formed in the
endoplasmic reticulum (ER) and are transported from cell to cell.
Which of the following best describes the mechanisms by which these enzymes would be transported from the cell
and into a new cell?
O A vesicle from the ER will pass through the plasma membrane via exocytosis, and will then be transported to a
new cell via phagocytosis.
O The enzymes will diffuse across the plasma membrane, and then form a vesicle in the extracellular matrix that will
be engulfed by the new cell via pinocytosis.
O The enzymes will pass through a channel protein to leave the cell, and then form a vesicle in the extracellular
matrix that will be engulfed into the cell via receptor-mediated endocytosis.
A vesicle from the ER will fuse with the cell membrane and release the contents into the extracellular matrix via
exocytosis, and then the plasma membrane will engulf the enzymes via receptor-mediated endocytosis.
Answer:
here
Explanatio
Answer:
D. A vesicle from the ER will fuse with the cell membrane and release the content in to the extracellular matrix via exocytosis an dthen the plasma membrane will engulf the enzyme via receptoe mediated endocytosis.
Explanation:
EDGE 2020 AP BIO
Which of the following is a right NOT guaranteed to workers by the Occupational Safety and Health Administration Act?
right to take safety training courses
right to a be paid certain wage
right to be informed about workplace hazards
right to review their medical records
Answer:
I want to say option D: right to review their medical records. Sorry if my answer is wrong
Right to review their medical records is not guaranteed to workers by the Occupational Safety and Health Administration Act. Hence option 4 is correct.
What is health administration?Health administration is defined as the administration of all non-clinical tasks necessary to run a healthcare facility, including daily management, staffing, budgeting, and financial management as well as long-term strategic planning to assure the success of the healthcare provider or system. With an MBA, students can get the knowledge and abilities necessary to succeed as business managers.
All employees are granted three essential rights under the Occupational Health and Safety Act: the right to information about health and safety issues. the right to take part in choices that can influence their health and safety. the ability to decline tasks that would endanger their health, safety, and the welfare of others.
Thus, right to review their medical records is not guaranteed to workers by the Occupational Safety and Health Administration Act. Hence option 4 is correct.
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Is water living (biotic) or non-living (abiotic)? *
O Biotic
Abiotic
What makes a water molecule polar? *
it has partial charges
Ο Ο
O it has more electrons than protons
O it has more protons than electrons
O it is neutral
Answer:
it has partial charges
The hydrogen gives a positive partial charge
The oxygen gives a negative partial charge
Oxygen is way more electronegative than hydrogen therefore the molecule will be polar.
Two factors concerning hydrochloric acid which should be controlled to produce valid results
Answer:
volume , temperature, same liquid.
Explanation:
use the same volume of acid.
use the same concentration of acid.
use the same temperature of acid.
pls help me urgently
Explanation: So just do this...
480 - 120 = 360 this is the answer for 60 and the last one is 480 +120 = 600.
I hope this helps.
opinion about dispersal and adaptation allow species to persist in changing environment!
Answer:
Explanation:
A plant specimen has seeds that are enclosed by a fruit. which type of plant is it? angiosperm gymnosperm monocot dicot
A plant specimen has seeds that are enclosed by fruit is a type of plant is called angiosperm.
What are Angiosperms?
Angiosperms are vascular plants. They have stems, roots, and leaves. Unlike gymnosperms such as conifers and cycads, angiosperm seeds are found in a flower. Angiosperm eggs are fertilized and grow into a seed in an ovary that is usually in a flower.
Thus, angiosperm a plant specimen has seeds that are enclosed by fruit is a type of plant.
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Which substance would be okay to come in contact with without the need for universal precautions according to OSHA's Bloodborne Pathogens Standard
Substances such as feces and nasal secretions can be contacted without the need for universal precautions.
What are OSHA's Bloodborne Pathogens Standard?The OSHA's Bloodborne Pathogens Standard requires that all human blood and certain human body fluids are treated as if known to be infectious for diseases such as HIV, HBV, Hepatitis B and C, etc.
This implies that personal protective equipments must be worn at all times when handling all human blood samples and this is known as universal precautions.
However, some substances such as feces, nasal secretions, sputum, sweat, tears and urine would be okay to come in contact with without the need for universal precautions.
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Which of the following cell organelles is thought to have once lived as a free-living
cell with it's own DNA?
Cell membrane
Mitochondria
Viruses
Ribosomes
Answer:
Ribosomes here is your answer
If I were measuring the pH at varying distances along a stream to test the impact on pH of the factory upstream. I would choose to measure the water above the factory which would represent which part of an experiment (control, independent, or dependent) Circle one.
Answer:
Dependent variable
Explanation:
The dependent variable in an experiment is the variable that the experimenter measures in an experiment. The dependent variable responds to changes made to the independent variable.
In this case, the pH of a stream is being measured at varying distances. If one is to measure the pH of the part of water above the factory, the pH being measured represents the DEPENDENT VARIABLE in the experiment.
You notice that some of your plants are growing at different heights. You want to know if the amount of water affects the growth of the plants and decide to construct an experiment. Your hypothesis states, "If a plant gets more water, then the taller it will grow". Identify the INDEPENDENT VARIABLE A) Amount of water the plants are given B) Plant height (growth) C) Amount of sunlight OD) Type of soil
Answer:
A is the correct answer
Answer:
A
Explanation:
hope this helps. .................
What is the first organ to respond to an increase in blood glucose concentration?.
Answer:
Pancreas
Hope it helps!
The idea that each living species has descended with changes from other species over time is called.
Answer:
Theory of Natural Selection
4. Which group makes up most of the world's animals?
amphibians
mammals
fish
insects
Insects group makes up most of the world's animals due to large number of species.
Which group makes up most of the world's animals?Insects in terms of numbers of species, insects represent the largest percentage of the world's organisms. There are more than 1 million species of insects that have been recorded and studied by scientists.
So we can conclude that insects group makes up most of the world's animals due to large number of species.
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Which is an example of how the body maintains homeostasis?
A. increasing thirst when cells are low on water
B. decreasing thirst when cells are low on water
C. shivering when it is hot
D. sweating when it is cold
Answer: A
Explanation:
Homeostasis works to promote balance in the body.
Answer:
The answer is A Increasing thirst when cells are low on water
sry if I'm wrong
Explanation:
You open a urine sample for testing and immediately detect a fruity odor. Which test result do you expect to be elevated using a urine dipstick
The test result that would be elevated due to the fruity odor is ketones.
What is urinalysis?Urinalysis is a chemical, physical and microscopical examination carried out on a urine sample. This can be used to detect a wide range of disorders such as:
urinary tract infections, kidney disease and diabetes.The dipstick method of urinalysis uses a stick that is made up of chemicals which are capable of detecting the following through a colour change:
Ketones,sugar,proteins,acidity, and blood.The presence of fruity odor in the urine sample signifies that there is excess ketone in the body due to ketoacidosis.
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!!!PLEASEHELP ME
Consider pioneer species and some of the characteristics that are likely to make them successful. Read the following statements about their potential characteristics and determine which one is unlikely
the answers are down below
The most unlikely characteristics of pioneer species is that they have long life cycles with slower growth and longer life spans.
What are pioneer species?Pioneer species are the species to first colonize and adapt to a particular habitat.
Pioneer species are usually simple organisms with limited nutrient requirement and ate mainly photosynthetic.
They usually have short life spans.
Thus, the most unlikely characteristics of pioneer species is that they have long life cycles with slower growth and longer life spans.
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