The skeletal system supports and protects the body and the muscular system is for movement.
Nucleic acids also typically contain phosphorous, and nitrogen plays an important structural role in nucleic and proteins. The proteins, being made up a diverse set of amino acids, have, in addition to carbon, hydrogen, oxygen, and nitrogen, the elements sulfur and selenium.
Answer:
Means to increase drag and prevent sinking is the correct answer.
Explanation:
Plankton avoid sinking by increasing their surface area and decreasing their density. Spines slow down sinking by adding surface area without increasing density. Defense against predation would be to sing below. Not the opposite.
