How does the extinction of a species affect humans ? a. extinction contributes to the loss is natural food sources. b. extinction generates new sources of medicine c. extinction keep air and water clean d. extinction makes the environment more pleasant

A because that animal is something else’s food then that animal decreases on number which means the other animal decrease in number and so on until it gets to the human population

A is the answer I believe

Six amino acids have side chains that are polar but not charged. these are serine (ser), threonine (thr), cysteine (cys), asparagine (asn), glutamine (gln), and tyrosine (tyr). these amino acids are usually found at the surface of proteins, as discussed in the proteins 2 module.