When does fertilization occur? When a sperm cell unites with an egg cell.
When an egg cell undergoes meiosis.
When a sperm cell undergoes meiosis.
When non-disjunction occurs.

Which of the following is a cost of urbanization? a-cities can provide a high standard of living. b-cities are hubs of entertainment and education. c-paving over land changes the environment. d-job opportunities are greater in urban centers.

Do plant cells perform cellular respiration?

What kinds of molecules can pass through the cell membrane without any problem?