C. The cell took in another ancient prokaryotic cell, which began living inside it.
Answer:
B. Is what the scientists manipulate in the experiment.
Explanation:
The Independent variable is not dependent, or doesn't rely, on another variable in the experiment. So, it would make the most sense that they would manipulate the Independent so that they can watch and see how the dependent variable reacts to the manipulation, or the change, in the independent variable.
Answer:Mercury, Venus, Earth, and Mars
Explanation:
The defecation reflex involves two postive feedback loops. these loops are the stretch receptors in the rectal walls and the sacral parasympathetic system. Defecation reflex empties the rectum by peristaltic movements push fecal matter from the sigmoid colon into the rectum. Then this distension of the rectal walls stimulates stretch receptors which results in defecation.
