Ablastula is
a. a digestive organ.
b. the innermost germ layer.
c. a layer of embryological tissue.
d. a hollow ball of cells in an embryo.

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.

lesson summarykaryotypes a genome is the full set of all the genetic information that an organism carries in its dna. chromosomes arebundles of dna and protein found in the nucleus of a eukaryotic cell.