Which pair of statements best describes an essential amino acid? a. it is an amino acid that contains peptide bonds. an example is proline. b. it is an amino acid that contains nitrogen. an example is aspartic acid. c. it is an amino acid that cannot be made by the body. it must be obtained from eating certain foods. d. it is an amino acid that can be produced by the body. vitamin supplements maintain healthy levels.

Which of the following is a cause of a dna mutation? o a. the linking of amino acid subunits into a long chain o b. the transcription of dna into rna o c. an error in the repair of damaged dna d. the diffusion of molecules across the cell membrane submit

Which part of the neuron below is indicated by the arrow, and what is its function? hormones send chemical signals throughout the body to regulate other body processes. hormones are chemical signals that are sent throughout the body to regulate other body processes. hormones send electrical signals throughout the body to regulate other body processes. hormones are electrical signals that are sent throughout the body to regulate other body processes.

Why does sexual reproduction increase the genetic variation in a species? a. sexual reproduction doubles the chromosome number. b. sexual reproduction produces organisms with no dna. c. the gametes in sexual reproduction are exact clones of the parents. d. a fertilized egg has a mixture of alleles from the two parents.