a control helps to increase the reliability of the results. it allows a scientist to compare it to other group(s) in an experiment. if a scientist notices a significant different btwn the control and the other groups, he can logically conclude that the independent variable has an impact on the dependent variable.
a variable is any factor, trait or condition that can exist in differing amounts or types. there are usually three tpes of variables in experiments: the independent, dependent and contolled. the independent variable variable is the one that is changed by the scientists to figure it's affect on something.
The villi of the small intestine use active transport to take up nutrients after concentration has reached equilibrium.
<h3>What is Active transport?</h3>
Active transport may be defined as the process that occurs against the concentration gradient and is mediated by carrier proteins. Metabolic energy is used to move ions or molecules against a concentration gradient.
During the process of digestion, the villi in the small intestine enthrall the soluble nutrients gradually. Over time, the concentration of nutrients in the villi acquires an equilibrium with the concentration in the gut. Until here, the nutrient uptake is carried by the process of passive diffusion.
But after attaining the equilibrium, the nutrient uptake is carried by the process of active transport.
The complete question is as follows:
What part of the body uses active transport to take up nutrients after concentration has reached equilibrium?
- Lungs
- Stomach
- Small intestine
- Liver
Therefore, the correct option for this question is C, i.e. small intestine.
To learn more about Active transport, refer to the link:
brainly.com/question/18434867
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Answer:
1) About 8.7 million.
2) They are being found everywhere.
The experimental group is the group you change from the normal. the fertilizer group is experimental