What is positive controls used for?

Answers

Answer 1
A positive control is a group in an experiment that receives a treatment with a known result, and therefore should show a particular change during the experiment. It is used to control for unknown variables during the experiment and to give the scientist something to compare with the test group.

Related Questions

apoorwa, What is the function of a nucleus in a plant cell and a endoplasmic reticulum

Answers

Answer:

It stores the cell's hereditary material, or DNA, and it coordinates the cell's activities, which include intermediary metabolism, growth, protein synthesis, and reproduction (cell division).

Explanation: :))

The buoyant force in Newtons at a point on the sphere is?

Answers

Answer:

I calculate the buoyancy force as: Volume of the sphere = Volume of the water displaced (Vdisplaced) = (4/3)πr3. Weight of the displaced water = Buoyancy force (B) = Vdisplaced× density of water.

I hope this is what you needed

Recognize the pattern of features that reveal the history of a species

Answers

Answer:

◊Identify evidence Darwin used to present his case for evolution.10-3• Compare artificial selection to natural selection.Artificial: humans change a species by breeding it forcertain traitsNatural: mechanism by which individuals that haveinherited beneficial adaptions produce more offspringon average than do other individuals.

Explanation:

Which action may increase the flask’s carrying capacity for rotifers?
A. decrease the number of microorganisms
b. introduce water fleas
c. decrease the size of the flask
d increase the number of microorganisms

Answers

The action that may increase the flask's carrying capacity for rotifers would be to decrease the number of microorganisms in the flask.

Carrying capacity

The carrying capacity of an environment refers to the maximum number of organisms of a particular species that the environment can support based on the resources it has.

Rotifers and microbes growing in the flask mean that both species would have to compete for the resources present in the flask. This competition will limit the reproductive capacity of each species.

As the population of the species decreases, the growth of the other is favored due to less competition.

With rotifers growing alone in the flask, there would be less competition for resources and more population growth.

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Answer:

increase the number of microorganisms

Explanation:

i just took the test

In a model of an atom, where would I find a valence electron?
O In the Nucleus
Randomly among the other electrons
On the last energy level
Valence electrons are not found on these models.

Answers

Valence electrons would be found in the outermost shell of atom models!

Hope this helps (:

what is the difference between nucleus and vacuole ​

Answers

Answer:

In cytology|lang=en terms the difference between vacuole and nucleus. is that vacuole is (cytology) a large membrane-bound vesicle in a cell's cytoplasm while nucleus is (cytology) a large organelle found in cells which contains genetic material.

Answer: A nucleus directs activity in a cell whereas the vacuole stores food and wastes in a cell.

How is the number of bonds carbon can make related to its ability to form molecules with many different shapes?

Answers

 because each carbon atom can form four chemical bonds to other atoms and because the carbon atom is just the right or small size to fit in comfortably as parts of very large molecules.

The number of bonds carbon can make is related to its ability to form molecules with many different shapes because: it can form four (4) covalent bonds, rings, straight chains, and wrench chains.

Carbon refers to a non-metallic and tetravalent chemical element which is represented with the chemical symbol C and it has an atomic number (number of protons) of six (6).

Generally, carbon (C) has the ability to form chains that are almost unlimited in length because an atom of carbon can bond to other carbon atoms.

This ultimately implies that, carbon (C) can form molecules with many different shapes as a result of the number of bonds carbon it can make.

Hence, the ability of carbon (C) form molecules with many different shapes is simply because of the following:

Carbon (C) can form four (4) covalent bonds.It can form rings.It can form straight and wrench chains.Carbon (C) atoms can bond to other carbon atoms.

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Plants exhibit movements in response to various
a) stimuli b) light c) water d) chemicals

Answers

Answer:

plants move towards to the source of light

I’m not sure what to put and I been on this question for a minute?!!

Answers

Answer:

For the growth of cells and tissues, and to well, produce more cells.

Explanation:

Cells are important for all organisms, from humans to singlecelled organisms. Cells do “die” and new cells are needed to carry out bodily functions.

what is sustainability ​

Answers

Meeting our needs without compromising the ability’s of our future generations to meet their needs.

please help!!
How do living organisms maintain homeostasis on a cellular level?

Answers

Answer:

Hello

To maintain homeostasis, unicellular organisms grow, respond to the environment, transform energy, and reproduce. A single-celled, or unicellular, organism does everything you would expect a living thing to do.

Answer: for living organisms to maintain homeostasis, unicellular organisms grow, react to the environment, convert energy, and reproduce.

Explanation: A single celled, or unicellular organism does everything you would demand a living thing to do.

Should college be free

Answers

Answer: I think it should be.

Explanation: People who don't have money or poor people will not be able to afford it.

Living organisms evolved in a world where they were constrained by the laws of physics and chemistry. Describe the two laws of thermodynamics and explain how each law impacts the structure of an ecosystem's food chain as energy flows from one trophic (feeding) level to the next

Answers

Answer:

The laws of thermodynamics are important unifying principles of biology. These principles govern the chemical processes (metabolism) in all biological organisms. The First Law of Thermodynamics, also known as the law of conservation of energy, states that energy can neither be created nor destroyed. It may change from one form to another, but the energy in a closed system remains constant.

Hi, you can ignore my previous question however I kindly ask of you to please answer this question,

What activity in excess is least likely to cause cancer?
A.] Smoking ciggies
B.] Sunbathing
C.] Malnutrition
4.] X ray exposure

Answers

Answer:

Smoking ciggies is known too cause cancer

Sunbathing has little risk but can cause skin damage, but tanning can cause cancer.

Malnutrition has a a high chance of cancer

X ray expose can but only in really high dosage (not the ones used in hospitals)

Explanation:

I would say that if 4 is talking more about The X ray´s used in hospitals and medical equipment, go with that one.

Which statement best describes a scientific law?

Answers

A would be the answer

Hello people ~
Cochlea is a part of
(a) hearing organ
(b) sound producing organ
(c) muscular organ
(d) air pollution

Answers

Answer:

hearing organ

Explanation:

Cochlea is. found inside the inner ear.It is hollow and spiral shaped bone .

A diagram attached

Answer:

(a) hearing organ

Explanation:

cochlea is a part of hearing organ which detect vibration or hearing

Which of the following are narrow blood vessels that restrict blood flow and have thin walls that allow gas exchange? Alveoli Veins Arteries Capillaries.

Answers

Arterioles are narrow blood vessels that restrict blood flow and Capillaries have thin walls that allow gas exchange.

What is blood vessels?

Blood vessels are channels that carry blood throughout your body.  They help to transport oxygen to vital organs and tissues, and also remove waste products. Blood vessels include veins, arteries and capillaries.

Veins bring blood to the right side of your heart.

Arteries branch into smaller vessels called arterioles. Both arteries and arterioles are very flexible. They get bigger or smaller to help maintain your body's blood pressure.

Capillaries have thin walls that allow oxygen, nutrients, carbon dioxide and waste products to pass through, to and from the tissue cells.

thus, Arterioles are narrow blood vessels that restrict blood flow and Capillaries have thin walls that allow gas exchange.

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Answer:

Capillaries

Explanation:

Capillaries are the tiniest vessels in the circulatory system. If the circulatory system is a network of roads, then capillaries are the side streets and alleyways that go to each building in a city. The majority of capillaries are so thin that blood cells must move through them singly. The thin walls of these confined tanks allow gas exchange.

Maintaining homeostasis involves many processes. One of these includes the excretion of waste. Our kidneys work very hard to filter blood of waste products and control how much water is kept in the body. The waste products and water make up urine. A dehydrated individual would have a concentrated urine that's a darker yellow in color than that of a healthy urine. Why is that?

Answers

Answer:

Please find the explanation below

Explanation:

As rightly said in this question, the kidney is the major excretory organ in our (human) system, which also helps maintain homeostatic balance between water and waste products. According to the question, the kidneys function to filter blood of waste products and control how much water is kept in the body.

Since urine is a mixture of the removed waste and water, a concentrated urine with a dark yellow color than normal indicates that the involved individual is DEHYDRATED i.e. low in water content of the body and hence needs water.

The urine of this dehydrated individual is this DARK YELLOWISH COLOUR because the kidney RETAINS THE SMALL AMOUNT OF WATER PRESENT IN THAT INDIVIDUALS BODY which ought to make the person's urine diluted, hence, the urine contains more of waste products (urea) and less of water, making it appear darker yellow than that of a healthy individual.

What is the function of the tube cell?

Answers

Answer:

The tube which conveys the male gametes of seed-bearing plants to the ovule.

Explanation:

The cell in the pollen grain that develops into the pollen tube.

Which choice most accurately describes the effect of energy on materials during absorption?
The glass absorbs the visible light wave and reemits its energy as visible light. It absorbs the ultraviolet and infrared waves,
then converts the energy into heat. The temperature of the glass increases due to the absorption.
The glass does not absorb the energy of any of the waves. The ultraviolet, infrared, and visible waves are transmitted
through the glass. The temperature of the glass does not change.
The glass transmits the visible light wave. It also absorbs the ultraviolet and infrared light waves and reemits these waves as
visible light waves. The temperature of the glass does not change.
The glass absorbs ultraviolet, infrared, and visible waves and converted all their energy into heat. The temperature of the
glass increases due to the absorption. None of the light waves were reflected or refracted.

Answers

Answer:

The glass absorbs the visible light wave and reemits its energy as visible light. It absorbs the ultraviolet and infrared waves, then converts the energy into heat. The temperature of the glass increases due to the absorption.

Explanation:

The results of an experiment often prompt new questions that further scientific investigation can answer. From the results of this experiment, name one new question that a new experiment can answer.

Answers

Here is one possible answer:

Do allergen-free pillows cause fewer germs to grow

Answer:

Explanation:

i agree with the answer down below

2.) Complete the diagram for the organization of life.


a.) ecosystem

b.) organelle

c.) organisms

d.) organs

Answers

Answer:

organelle ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌

In the completed diagram the last organization of life the third structure is organelle. Thus, option B is correct.

What is organisation level in the living things?

In the case of living things first of all they are made up of the cell and the cell has been known as the basic and fundamental unit of the living things, after that cells combined and they form tissue, or we can say that group of cell is known as tissue.

Tissues combined together and they form muscles and these muscles are of several types and after that muscles combined together and they form organ and each of the organ of the body is made up of different types of tissue. Like heart is made up of such type of tissue that never takes rest.

At last the organs or we can say that two three organs combined together to form the organ system of the body such as nervous system, respiratory system, and these systems combinedly form the whole organism.

Therefore, In the completed diagram the last organization of life the third structure is organelle. Thus, option B is correct.

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Currently, most organs that are harvested for transplant are transported from the donor to the recipient packed in ice and must be implanted within a matter of hours. How is organ culture an improvement on this transport method? Organs that are packed in ice can be damaged by frostbite during transit. Cultured organs can be kept alive for several weeks before transplant. Extra culture medium is easier and cheaper to transport than extra ice. Organ cultures can be shipped as cargo rather than hand delivered.

Answers

The organ culture is an improvement on this transport method as cultured organs can be kept alive for several weeks before transplant.

What do you mean by an Organ transplant?

It is a method to place a specific organ that is taken from the body of another individual. The doctors remove an organ from another person and place it in your body.

Every organ can not behave in the same way on the outside of the body, so they are kept in cultured solution to function properly and kept alive. Putting the organs in a cultured solution reduces the chances of organ rejection.

Therefore, the organ culture is an improvement on this transport method as cultured organs can be kept alive for several weeks before transplant.

To learn more about Organ culture, refer to the link:

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When the level of carbon dioxide in the blood is too high, the excess carbon dioxide reacts with water and produces carbonic acid. the carbonic acid causes the blood ph to become more acidic. when the blood ph becomes too acidic, chemoreceptors in the brain instruct the body to react and maintain homeostasis in blood ph. which of these responses by the body would eliminate the excess carbon dioxide and help maintain homeostasis in blood ph?

Answers

Answer: Breathing more deeply and frequently

The carbonic acid causes the blood ph to become more acidic. when the blood ph becomes too acidic, chemoreceptors in the brain instruct the body to react and maintain homeostasis in blood ph.

What stops functioning of the enzymes?

At a pH too far from 7.4, enzymes in the blood will stop functioning properly. The pH of blood is regulated 7.35 and 7.45. pH shows acid-base balance in the body and maintains a healthy balance of acidity and alkalinity.

Balance of acid-base provides optimum condition to enzymes to perform proper function. As, enzymes required optimum pH range for functioning properly, pH too far from 7.4 can denature the enzymes. Enzymes will lose its shape and will not function properly at high pH.

When the level of carbon dioxide in the blood is too high, the excess carbon dioxide reacts with water and produces carbonic acid. the carbonic acid causes the blood ph to become more acidic. when the blood ph becomes too acidic, chemoreceptors in the brain instruct the body to react and maintain homeostasis in blood ph.

Therefore, The carbonic acid causes the blood ph to become more acidic. when the blood ph becomes too acidic, chemoreceptors in the brain instruct the body to react and maintain homeostasis in blood ph.

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Describe a genetic disorder which is caused by mutation, its causes and effects to a person.

Can any one please help me in this biology question?

Answers

Answer:

Do you mean something like conjoined twins/triplets?

Explanation:

Conjoined twins are born with their bodies connected together. Sometimes by the head, stomach or leg and 70% of conjoined twins are female. Hope that helped!

pls, I need help with this

Answers

Answer:

C

Explanation:

Cells shrink when loses water.

Acid, mucus, and enzymes are just some of
our
a) chemical defenses
b) specific immune response
c) should be avoided

Answers

The answer is C chemical defenses

Hydrogen bonds can form between regionsof polar molecules that are. . .

Answers

Explanation:

polar molecules give up electrons to hydrogen atoms. polar molecules contain partially charged regions that attract other polar molecules...

Why are tigers killed Or Why are they endangered?

No copied answers
Best answer will be marked brainliest and spam will be reported​

Answers

Because some species are dangerous to man

Answer:

because they can be sold dearly or their skins, it will be possible to make stuffed animals out of them, it will also be possible to sell them to countries where they do not exist and get a lot of money


How are enzymes different from other catalysts? *
A enzymes are catalysts specifically for reactions involving organic molecules
B enzymes increase the activation energy for a reaction while catalysts lower it
C enzymes are used for DNA while catalysts are used for RNA
D enzymes follow the lock-and-key model while catalysts follow the insert-card-here model

Answers

Answer:B

Explanation:The main difference between catalyst and enzyme is that catalyst is a substance that increases the rate of a chemical reaction whereas enzyme is a globular protein that can increase the rate of biochemical reactions. The inorganic catalysts include mineral ions or small molecules

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