Why must an in vitro observation be confirmed in vivo?
A. A living thing does not make its own enzymes.
B. A test tube is exactly like a living cell.
O
c. Some enzymes behave unnaturally in a test tube.
O
D. Observations in a test tube are easy to make.

Which describes a difference between cephalopods and gastropods? cephalopods have a water vascular system, and gastropods have an open circulatory system. cephalopods live only in ocean environments, and gastropods live in a variety of environments. cephalopods have a simple nervous system, and gastropods have a complex nervous system. cephalopods are the largest group of mollusks, and gastropods are the smallest group of mollusks.