Answer:
Nitrogen is a crucially important component for all life. It is an important part of many cells and processes such as amino acids, proteins and even our DNA. It is also needed to make chlorophyll in plants, which is used in photosynthesis to make their food.
I’m not sure but it might be the third one
Answer:
Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period.
Answer:
semi-conservative
Explanation:
Each helix that is created contains one strand form the helix from which it was copied
A solution that maintains its ph within a narrow range is called a buffers.
