question: Where so parasites go to survive?
Options:
- (A) in a field
- (B) away from a host
- (C) heat produced
- (D) loose soil
- (E) in the water
- (F) on a host
- (G) Most plants
- (H) retina
answer: Some parasites live on the surface of their host. Survival is to live, to live means hope. Some parasites survive on the surface of their host.
The answer is (F)

question: What has circulatory system with a two-chambered heart?
Options:
- (A) sharks
- (B) trout
- (C) pan
- (D) toads
- (E) Birds
- (F) animals
- (G) mammals
- (H) Man
answer: Fish have a circulatory system with a two-chambered heart. Fish species include salmon and trout. Salmon and trout have a circulatory system with a two-chambered heart.
The answer is (B)

question: What does a hairy organism have under its skin to help insulate the body?
Options:
- (A) fat
- (B) hair
- (C) food
- (D) cell
- (E) nerves
- (F) coat
- (G) fur
- (H) marrow
answer: Mammals have a layer of fat under the skin to help insulate the body. If it has hair it is a mammal. An organism with hair has a layer of fat under the skin to help insulate the body.
The answer is (A)

question: Which type of system do most animals without backbones have?
Options:
- (A) sensory neurons
- (B) Veins and arteries.
- (C) Nervous system
- (D) Stereo system
- (E) Root system
- (F) to move people
- (G) Skeletal system
- (H) insects
answer:
Most invertebrates have a nervous system. Invertebrates are animals without a backbone. Most animals without backbones have a nervous system.
The answer is (C)