phenylindanes I'm pretty sure.
An adaptation that makes bipedalism possible is the need to get around. If your slithering on the ground, you could get diseases, or get hurt.
The difference between respiration and breathing is their functions. Breathing is when your body uses your lungs to inhale and exhale oxygen. Respiration is a chemical reaction where your body uses oxygen to eliminate or break apart Glucose so it could give you energy.
Hopefully this helps :)
<span>are we talking human reproduction? in this case only 1 egg is implanted. in unusual cases there could be 2 eggs implanted meaning fraternal twins. if 1 egg splits, we get identical twins. with only one egg implanted, there is only 1 kid being produced.
the female has eggs stored from birth. 1 ovary 'pops' once a month to either be discarded via a period or implanted after fertilization. multiple eggs released is usually the effect of fertility drugs making many eggs get released at once. this is unusual unless fertility drugs are in use</span>