Ques and Ans: The molecules secreted by activated b cells are part of the:
Options:
- (A) immune system
- (B) Organic compounds
- (C) Energy.
- (D) an organism's body
- (E) acetic acid
- (F) harmful substances
- (G) Chemical energy
- (H) Veins and arteries.
(A)
Explanation for the Ans above: [[Plasma cells are activated B cells that secrete antibodies. Antibodies are manufactured by the immune system. Plasma cells are activated B cells that secrete immune system molecules.]]

Ques and Ans: Mutations are what to evolution?
Options:
- (A) Plants growth
- (B) essential
- (C) optional
- (D) competition
- (E) dangerous
- (F) non essential
- (G) voluntary
- (H) allow growth
(B)
Explanation for the Ans above: [[Mutations are essential for evolution to occur. When that occurs, several things happen. Mutations are essential for evolution happen.]]

Ques and Ans: What lack respiratory and excretory systems?
Options:
- (A) They may not survive.
- (B) members of their own species
- (C) platypus
- (D) humans
- (E) crinoids and blastoids
- (F) passenger pigeons
- (G) graptolites
- (H) whales
(E)
Explanation for the Ans above:
[[Echinoderms lack respiratory and excretory systems. Echinoderms in the diorama include the crinoids and blastoids. Crinoids and blastoids lack respiratory and excretory systems.]]