Absolute dating uses the half-life of an element.
Answer:
any of numerous complex proteins that are produced by living cells and catalyze specific biochemical reactions at body temperatures
B. trenches .......................
nebular hypothesis
The most widely accepted theory of planetary formation, known as the nebular hypothesis, maintains that 4.6 billion years ago, the Solar System formed from the gravitational collapse of a giant molecular cloud which was light years across. Several stars, including the Sun, formed within the collapsing cloud.
a. chloroplast and cell wall
The chloroplast contains chlorophyll, which is the stuff that makes plants green. So animals do not have a chloroplast. Only plants have a cell wall and it is what helps plants maintain their shape. Hope this helped! :)