Answer:
c) repeat the cell cycle continuously
Explanation:
Cell division is a normal phenomenon for all cells as this is the way the cell reproduces and gets repaired in living organisms. However, some cells, due to mutation, keeps dividing and proliferating to form tumours. These cells are called CANCER cells. A normal cell undergoes cellular repair at certain checkpoints of the cell cycle. The checkpoints are necessary to determine a faulty cell and stop its division.
However, cancerous cells do not undergo any repair, which is why they do not enter the G0 phase as mentioned in the question. They keep on dividing out of control without death by repeating the cell cycle continuously.
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. 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. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division.
Answer:
the somatic nervous system and the autonomic nervous system
Explanation:
The somatic nervous system is responsible for both sending and receiving sensory and motor information to the central nervous system.
The autonomic nervous system is responsible for regulating involuntary body functions. For example, heart rate, breathing, and digestion.
