B.) Ulnar aspect of the hand
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.
Seeds have cotyledons from where they can draw their nutrient in their early stages of development. Pollens must draw their nutrient from their environment from the start.
Seeds have an outer coating (testa) that protects the embryo and enable it to remain dormant in the soil until right conditions for growth set forth
Seeds have a fully developed embryo that can begin to grow immediately there are right conditions. However, pollen has a single cell instead of an embryo, which must undertake cell division and specialization before beginning to germinate
