The growth of plants and formation of land mammals characterized the paleozoic era.

your answer is given below..
The environment is rich in infectious agents that transmit disease through pathogens.
If the immune system fails to produce proteins (Antibodies) it can cause a disease. This is because our immune systems are very needed so if our immune system decides to fail to produce its proteins, our body will become overwhelmed and could possibly cause us to die! :(
Answer:
Chemical digestion actually starts in the mouth when our saliva mixes in with the food. So, A. wouldn't really be correct. It's not the molars that are doing the chewing, but rather your jaw muscels. I don't even know what pepsin is... <u>C. would probably be your best bet because it's your saliva that breaks down your food and helps you chew it.</u> And D. your tongue just helps to move the food around...
Explanation:
Hope this helps you!!!
<span>There are 46 chromosomes in a human zygote.
</span><span>Source(s):
Google. I also know this, just to make sure you know my answer is right!
</span><em>When the gametes join they form a cell called a zygote. Human sperm and eggs contain 23 chromosomes</em><span><em>. Human zygotes contain </em></span><em>46 chromosomes</em><span><em>. The type of cell division that produces gametes with half the normal chromosome number is called meiosis.</em></span>