Cancer is best described as OPTIONS:
- a type of genetic engineering
- the merging of sex cells
- abnormal cell division
- tissue that stops growing
A: abnormal cell division

Which of these statements about nonrenewable resources is true? OPTIONS:
- They are inexpensive.
- They help keep the air clean.
- They can take millions of years to form.
- They are used because they are easily removed from the ground.
A: They can take millions of years to form.

Why do planets stay in orbit around the Sun? OPTIONS:
- attraction of gravity
- effect of inertia
- frictional force
- rotational force
A: attraction of gravity

Down feathers are used by many sleeping bag manufacturers because down feathers are OPTIONS:
- fire resistant.
- comfortable padding.
- good insulators.
- water resistant.
A:
good insulators.