Q: Mammals must eliminate waste products that their bodies produce. Which organ helps mammals eliminate bodily waste?

OPTIONS:
- appendix
- kidney
- pancreas
- stomach
A: kidney
Q: Which has the greatest effect on aiding the movement of blood through the human body?

OPTIONS:
- tension
- friction
- density
- gravity
A: gravity
Q: Which of the following is a characteristic of all chemical changes?

OPTIONS:
- A different state of matter is produced.
- Some mass is converted to energy.
- Some form of light is given off.
- A new material is formed.
A: A new material is formed.
Q: Researchers are developing new types of crop plants with desirable characteristics such as disease resistance and drought tolerance. Crossing plants so that the next generation will express desirable traits is best described as

OPTIONS:
- selective breeding.
- natural selection.
- genetic engineering.
- gene sequencing.
A:
selective breeding.