The nucleus intructs cells to do their activities
I think it is A
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Answer/ explanation :
Reflex response is an involuntary, automatic and rapid response to a stimulus.
It's is controlled by the brain stem.
Reflex actions cannot be controlled. They are coordinated by nerves which moves to and fro in the spinal cord without a direct involvement of the brain.
Examples of a reflex response
Sneezing, coughing, yawning, toughing a hot object, blinking of the eyes.
There are two types of reflex response
Autonomic reflex arc
The somatic reflex arc
The reflex responses happens so quickly because they do not have to be processed by the brain before taking place.
Answer:
Cell membranes are selectively permeable which means it allow certain molecules to move across it into and out of the cell. Cells need to be able to transport these substances to live and grow.
Transport of ions, water maintains the osmotic pressure of the cell. Transport of sugars like glucose is necessary to generate energy for the metabolic activities of the cell. Gases like CO2 are waste products of metabolic reaction which are removed by the cell through the cell membrane. Amino acids are required to make proteins.
Transport across cell can occur through active and passive transport and transport of these substance are necessary for a cell to live and function properly.
<span>Mitosis is carried out for growth and development processes. The cell divide and multiply for growing and removing the worn out cells/damaged cells. Two identical daughter cells are formed in mitosis. Errors in the same may cause genetic disorders, Sex cells divide by the process of meiosis. </span>