Q: Answer the question

When the pesticide DDT was first used, it killed nearly every mosquito it touched. Within a few years, however, many mosquitoes became resistant to DDT and survived. What enabled this to happen?
OPTIONS:
- meiosis
- migration
- immune responses
- gene mutations

A: gene mutations

Q: Answer the question

Some plant cells are coated in a waxy layer that prevents water loss. This specialization is found in which plant cells?
OPTIONS:
- internal stem cells
- internal root cells
- cells on the plant surface
- cells in the plant reproductive system

A: cells on the plant surface

Q: Answer the question

A student conducts an investigation. In order to make a valid conclusion, she must
OPTIONS:
- have a testable hypothesis.
- place the data in a graph.
- use the best technology.
- test multiple variables.

A:
have a testable hypothesis.