The R group is what allows amino acids to form macromolecules with different properties. every amino acid has the same basic structure, the only difference is what the R group is made up of. The similarities allow the amino acids to form a chain while the differences allows them to have different functions. Hope this helped!
<span>The formation of the fertilization envelope (slow-block to polyspermy) requires an increase in the availability of </span>calcium ions.
Slow-block to polyspermy is also called cortical reaction. In this reaction, the sperm will be permanently blocked by cortical granules. The release of calcium ion will trigger this reaction.
I believe you're looking for "invasive species"
The system that is responsible for breaking down food and releasing essential nutrients and other substances that the body needs and requires is the digestive system.
