Which two animals are able to generate internal heat to maintain their body temperature in a cold environment

Which term refers to the total dollar value of the goods and services produced in a country in a year?

Nucleic acids offer variability because they contain alternate forms of genes called .

You are studying a protein that you call protein x. there is an aspartic acid at a key position in protein x which is important in the folding and stabilization of that protein. if this aspartic acid is changed to a different amino acid, which type of amino acid substitutions is most likely to allow the protein to fold normally?