Before there was any life on earth, which gas was absent from the ancient atmosatmosphere?

1) oxygen

2) ammonia

3) nitrogen

4) methane

Use this information to answer the following question. A large population of laboratory animals has been allowed to breed randomly for a number of generations.

The cell membrane is involved in all the following functions except A. containment B. Passive diffusion C. reproduction D. Active transport

Can farming and conservation go hand in hand? how?

T/F Permanent magnets can never be demagnetized.

What happens to the carbon in an organisms body after it dies?

Which rays of the electromagnetic spectrum are responsible for causing sunburn when you spend too much time exposed at the beach? A) Ultraviolet B) X-rays C) Gamma D) Visible E) Infrared Correct answer will be given the Brainliest! : D

Food and medical procedures can expose people to radiation. Therefore, the effects of radiation from a nuclear power plant are not a reason for concern. True False

What are 2 characteristics of tropism?

Rubbing the balloons against the woolen fabric or your hair creates static electricity. This involves negatively charged particles (electrons) jumping to positively charged objects.

Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle? A) gamma aminobutyric acid B) acetylcholine C) cholinesterase D) norepinephrine