Which of the following aquatic ecosystems is likely to have both a littoral and benthic zone? a Lake

b Open ocean

c Coral reef

d None of the above

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.