Answer: no body cavity—acoelomates; body cavity not completely lined with mesoderm—pseudocoelomates; body cavity completely lined with mesoderm—coelomates
Endocrine system regulation slowly happens but produces long-lasting effects, whereas nervous system regulation quickly takes place with short-term effects.
Endocrine system can regulate many things in the body that control the metabolism. The effect shouldn't be instant, but it should be good for long term effect. Nervous system need a much faster reaction because it responsible for "fight or flight" reaction. A slow nervous system will cause the organism caught by predator easier.
We need the options in order to answer
D. Lipids would be your answer
the answer for number 12 is 1.00 g/mL