Answer:

1.It is the only planet that has an atmosphere containing 21 percent oxygen. It is the only planet that has liquid water on its surface. It is the only planet in the solar system that has life. The Earth is the only inner planet (Mercury, Venus, Earth and Mars) to have one large satellite, the Moon.

2.Parthenogenesis is of normal occurrence in the life-cycle of many Hymenoptera. Generally the larval is the feeding, the imaginal the breeding, stage of the life-cycle. Their life-cycle, however, the structure of the reproductive organs and their whole organization proclaim them to be Bryophyta.