It is the circulatory system and respiratory system.
Answer:
Q1ans-Every cell in the human body contains protein. The basic structure of protein is a chain of amino acids. You need protein in your diet to help your body repair cells and make new ones. Protein is also important for growth and development in children, teens, and pregnant women
Q2ans.All the above
Explanation:
1). Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing.
2) is pic
D. The pathogen had been weakened
Four ATP molecules are produced during the Krebs cycle. The final step of cellular respiration is the electron transport chain.