"what is the function of the carapace? what two body systems in rats perform equivalent functions? "

The carapace or shell is an exoskeleton or external skeleton found in certain invertebrates. The carapace provides protection and rigidity to the organism. In rats the skeleton gives rigidity and protects organs. Also, the muscular system helps in maintaining shape and helps protect many organs. Hence the skeleton and muscles in rats perform equivalent functions as the carapace of other animals.

The basic repeating unit of nucleic acids are known as nucleotides. a nucleotide consists of three distinct chemical groups.

Reproduction i think