Question

multiple choice question
the human brain consists of more than 50 million ______ in an area of one cubic centimeter.

○ chromosomes
○ nerve cells
○ neurotransmitters
○ amino acids

Explanation:

To solve this, we analyze each option:

• Chromosomes are in cells (like in the nucleus) and not the main component of brain tissue in terms of quantity in a cubic centimeter of brain.
• Nerve cells (neurons) are the fundamental units of the brain's structure and function. The brain has a vast number of nerve cells, and the quantity of over 50 million in a cubic centimeter aligns with the density of nerve cells in brain tissue.
• Neurotransmitters are chemical messengers between nerve cells, not the main "components" counted in such a volume in terms of cell - like structures.
• Amino acids are building blocks of proteins and not the main structural units of the brain in the context of this question.

Answer:

B. nerve cells