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.
<u>Answer:</u>
Carbon is found in hydrosphere in the form of dissolved carbon in ocean and sea water during the gas exchange process.
<u>Explanation:</u>
- Carbon cycle is the process of transformation of carbon in different forms. From atmosphere, the carbon gets into hydrosphere during the gas exchange processes.
- During this gas exchange process, the carbon is dissolved in the ocean water which is later utilized by marine plants to conduct photosynthesis.
- There is a continuous transformation of carbon from lands, plants to atmosphere and from atmosphere to hydrosphere.
