Answer:
ice on the tundra or soil that is always frozen
Explanation:
I believe it’s A I think, I think I’m right
Answer:
The answer is: Clonal selection produces memory cells that are long-lived and can recognize the antigen in the future.
Explanation:
Answer: high-energy primary cosmic-ray particles interact with air nuclei high in the atmosphere, initiating a cascade of secondary interactions that ultimately yield a shower of electrons, and photons that reach ground level.
Explanation: