1. Floating organisms that drift with the ocean current and form the base of many food chains are known as plankton
seaweed
jellyfish
algae
squid

2. percent of marine life lives in the upper zone of the ocean that receives sunlight.
75
90
40
80
50

90

Explanation:

its true mn

The correct answer is option c- nearly all mammals descended from common ancestors.

Human cervical vertebra consists of 7 bones from top to bottom:

-C1

-C2

-C3

-C4

-C5

-C6

-C7

Cervical vertebra are located just below the skull are the neck bones that control the neck movements. In humans, cervical vertebrae are the smallest of all vertebrae. In different organisms, the size of these vertebrae vary.