Answer:
First one
Explanation:
Only answer that makes sense.
Double-stranded DNA loops around 8 histones twice, forming the nucleosome, which is the building block of chromatin packaging. DNA can be further packaged by forming coils of nucleosomes, called chromatin fibers. These fibers are condensed into chromosomes during mitosis, or the process of cell division.
Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
During DNA packaging, long pieces of double-stranded DNA are tightly looped, coiled, super coiled, and folded so that they fit easily within the cell. This highly compacted DNA is then arranged into structures called chromosomes.
Answer:
Gas exchange occurs at two sites in the body: in the lungs, where oxygen is picked up and carbon dioxide is released at the respiratory membrane, and at the tissues, where oxygen is released and carbon dioxide is picked up.
Explanation:
