Flucuated between hot and cold periods
Answer:
B. Proteins
Explanation:
Proteins make up many different things in our bodies. Proteins are the building blocks of organelles.
Ex- Ribosomes are organelles that are made of RNA and Protein, and they also make proteins.
MyB Protein is a protein that help build the immune system and give support to fight off diseases.

<h2>Fixation</h2>
Nitrogen in its gaseous form (N2) can’t be used by most living things. It has to be converted or ‘fixed’ to a more usable form through a process called fixation. There are three ways nitrogen can be fixed to be useful for living things:
<h3>Biologically: </h3>
Nitrogen gas (N2) diffuses into the soil from the atmosphere, and species of bacteria convert this nitrogen to ammonium ions (NH4+), which can be used by plants. Legumes (such as clover and lupins) are often grown by farmers because they have nodules on their roots that contain nitrogen-fixing bacteria.
<h3>Through lightning: </h3>
Lightning converts atmospheric nitrogen into ammonia and nitrate (NO3) that enter soil with rainfall.

Answer:
B and E
Explanation:
Because thats what stealthy means
The answer is b because water has a PH of 1 and lemon juice is very acidic