This was because one cannot view a single strain of DNA as it is too small for one to visually comprehend.
Answer: The correct answer is D. the central nervous system and the peripheral nervous system.
The nervous system is a complex system that is made up of nerves and nerve centers in different organisms that carries messages to and from the brain and the spinal cord to send them into various parts of the body.
It is primarily divided into-
1) CNS that is central nervous system ( made up of brain and spinal cord). The CNS is responsible for the voluntary functions of the body.
2) PNS that is peripheral nervous system ( possess cranial and spinal nerves arising from brain and spinal cord respectively). It controls the involuntary functions of the body.
Answer:
- Respiratory system
- Nervous system
- Circulatory system
- Integumentary system
- Endocrine system
Explanation:
During excessive hard work or sports, the respiratory system acts to provide sufficient oxygen for energy supply (ATP) - a process takes place in mitochondria. At the very beginning, the respiratory system is active. If the person doesn't intake sufficient water, he will feel tired because of heavy breathing that increases body temperature and affects metabolic reactions. A supply of water would help decrease the respiration need and so support other systems.
The nervous system (hypothalamus) regulates the body temperature which is necessary for metabolic reactions taking place within the body, i.e. homeostasis. During and after exercise, the water intake was not sufficient, this means that the hypothalamus would work to maintain the temperature as well as other metabolic mechanisms. In the case of less water intake, the nervous system would be in stress.
The circulatory system acts to transport blood and oxygen to all parts of the body. During sports activities, the oxygen supply would be high to maintain energy supply. This takes place with the combined action of the circulatory system and respiratory system. For optimal functioning, the circulatory system needs fluids (water) intake because sufficient water is already lost during sports.
The integumentary system is the system that directly protects the body from damages including dehydration. Therefore, in this case, it will be highly active.
The endocrine system consists of glands that produce hormones to control body metabolism. The body metabolism, as mentioned before, is driven through water availability. The reduced water in the body would also put the endocrine system under pressure.
