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.
In adults, stem cells remain undifferentiated until they are needed to repair or replace other cells. Stem cells can produce cells that are identical to themselves.
Answer:
The statement is false.
Explanation:
Passive transport moves molecules from one side of the membrane to the other with the energy of the chemical gradient (or concentration gradient). Otherwise, active transport uses the hydrolyzation of ATP to gain energy in order to move molecules across the membrane without taking into account the gradient.
I think the answer to this is D.
