Question

1. identify if the statement is true or false. a) true b) false nitrogen is an essential component of amino acids and proteins. 2) identify if the statement is true or false. a) true b) false photosynthesis is a step in the global nitrogen cycle. 3) identify if the statement is true or false. a) true b) false water expands when it crystallizes and freezes.

Explanation:

1. Nitrogen is an essential component of amino - acids and proteins as nitrogen atoms are part of the amino group in amino - acids. So, the statement is true.
2. Photosynthesis is not a step in the global nitrogen cycle. The nitrogen cycle involves processes like nitrogen fixation, nitrification, denitrification etc., but not photosynthesis. So, the statement is false.
3. Water expands when it crystallizes and freezes. This is because the hydrogen - bonding in ice causes the water molecules to arrange in a more open, hexagonal lattice structure compared to the liquid state. So, the statement is true.

Answer:

1. A. True
2. B. False
3. A. True