Answer:
2.) vertebrates have endoskeletons. some examples are...fish, birds, mammals, amphibians, and reptiles
The answer is 2. This is why their autosomal cells are referred to as diploid in chromosome number. The gametes have only one set of chromosomes. The homologous pair (sister chromosome) separate during meiosis I. If there was an extra chromosome in addition to this set then this would cause a condition called aneuploidy.
Answer:
The unified cell theory states that: all living things are composed of one or more cells; thecell is the basic unit of life; and new cells arise from existingcells. Rudolf Virchow later made important contributions to this theory.
The answer, I believe is answer of 2nd option...