Q: Channel proteins and carrier proteins help substances diffuse across what? Choices: - endoplasmic reticulum - ribosomes - cytoplasm - cell membrane A:
cell membrane

Q: What is the low level of radiation that occurs naturally in the environment called? Choices: - temperature radiation - neon radiation - consequence radiation - background radiation A:
background radiation

Q: Q: The nitrogen that enters living systems by nitrogen fixation is successively converted from organic nitrogen back into nitrogen gas by what? Choices: - algae - pollen - viruses - bacteria A:
A: bacteria

Question: Q: Receptors for what chemical messengers recognize molecules with specific shapes and side groups, and respond only to those that are recognized? Choices: - acids - chromosomes - enzymes - hormones A:
Answer: hormones

*Question*
Q: Transforming from a caterpillar to a butterfly requires a lot of what? Choices: - Water - fuel - food - energy A:
**Answer**
energy

Q: Q: What forms when water vapor condenses around particles in the air? Choices: - wind - storms - humididty - clouds A:
A: clouds