The answer for this question is C, I just did my final for Biology and got a good score in it.
Hope it helps!
Coral reefs are built by coral polyps as they secrete layers of calcium carbonate beneath their bodies. And inside each coral poly lives single-celled algae called zooxanthellae. So basically in simplistic terms, coral polys create coral reefs and algae is in coral polys which also goes into coral reefs when they are made.
<span>It binds itself to the receptors present on the surface of the cell membrane, which activates the enzymes present inside cell. Then It passes through the cell membrane and attaches itself to a receptor protein present in the cytoplasm.
It passes on the signal to the secondary messengers inside the cell, which activate the receptors on the cell membrane.</span>
The answer would be A. carbohydrates (carbs) because carbs are generally composed of sugars and glucose (as an example) has the ratio between carbon, hydrogen and oxygen in a 1:2:1 ratio in its form: C6H12O6