Answer:
DNA and ATP 2. proteins and lipids 3. chitin and starch ... Singer proposed the fluid mosaic model of the cell membrane in which the cell membrane consists of a double lipid layer with proteins embedded in it to act as name tags or to aid in movement of larger molecules across the membrane.
Explanation:
He used a simple microscope
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.
The two gasses that make up 99% of the earth's atmosphere are nitrogen and oxygen.
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