Question

Identify one of the key external difference between vertebrates and invertebrates.

Answer 1

Vertebrates have a bilateral symmetry due to which their entire body is divided into right and left halves while the invertebrates either have radial symmetry or the bilateral symmetry. Therefore, option D is correct.

The other basic differences between the vertebrates and the invertebrates are that vertebrates have a spinal cord and a backbone while invertebrates lack them, vertebrates have well developed brain, lungs or gills in respiratory system and closed circulatory system.

Answer 2

The correct answer is D)