Which of these food molecules is used as an energy source in cellular respiration A: ATP
B: Triglycerides
C: phosphorus
D: glucose
E: proteins

Although there are a limited number of amino acids many different types of proteins exist because..

This is a situation in which genes are attached to an organism's sex chromosomes; the sex of an organism influences the expression of a gene.

During crossing-over, a. genetic material is exchanged between nonsister chromatids, resulting in new combinations of alleles. b. nonsister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. c. one homologous chromosome of a tetrad is exchanged with another tetrad, resulting in new combinations of alleles. d. sister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. e. genetic material is exchanged between sister chromatids, resulting in new combinations of alleles.