Arrange these groups in the order that they first appear: birds, reptiles, amphibians, dinosaurs, fish.
(a complete sentence is not required)

The groups appeared in the following order:
Dinosaur followed by fish and then amphibians, reptiles and birds. The last group to exist in nature are the mammals which evolves from a reptilian ancestors. 

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.