1)………………………… grow in the leftover spots of the natural world that are too harsh or limited for most other organisms. They are pioneers on bare rock, desert sand, cleared soil , dead wood, animal bones, rusty metal, and living bark. Able to shut down metabolically during periods of unfavorable conditions, they can survive extremes of heat, cold, and drought.

2). …………….includes, in insects, the transformation of a maggot into an adult fly and a caterpillar into a butterfly and, in amphibians, the changing of a tadpole into a frog.The transformation of a maggot into an adult fly and of a tadpole into an adult frog are examples of it

3) The correct regulation of cellular processes is critical to the normal function of an organism, including cell growth, proliferation, differentiation, gene expression, and ………………….. Signal transduction pathways.

4) The discoveries of a vast and previously unsuspected extinct ………………… of the American continent of the Tertiary period, as interpreted by the palaeontologists Leidy, Cope, and Marsh, has thrown a flood of light upon the early history of this family, and upon its relations to other mammals.

5) A cell can be host to a virus, a legume plant can be host to helpful nitrogen-fixing bacteria, an animal can be host to a………………… worm, e.g., a nematode.

6)Fisher's research interests include the ecology of hydrothermal-vent and cold-seep organisms living on the ocean floor, including the wide range of ………….. And chemical processes on which their life depends.

7)In temperate climates, it is a…………………. Tree that looses its leaves before blooming and when the temperature drops down to about 30°F. Flowers - Flowers are solitary and are up to 4-5 in (10-12.5 cm) wide.