1.The main difference between vertebrates and invertebrates is the
presence of the backbone in the former. What do these backbones
provide the vertebrates?

2.Which of the following statements is true about ferns?
A.They produce seeds and flowers.
B.They have seeds, stems, and leaves.
C.They do not have roots, stems, and leaves.
D.They are seedless plants with roots, stems, and leaves.