Answer:
The 3.9 billion year old rock has undergone three half-lives (3.9 divided by 1.3 = 3). After 3 half-lives, 12.5% of the potassium-40 remains undecayed.
Explanation:
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.
Answer: B
Reason: rural farmers may lose their income
Answer:
C) Unrestricted whaling could lead to their extinction.
Explanation:
The whaling is a process of hunting and killing whales so as to get the meat, oil and whalebone so that they can be sell it out commercially. The trade of whale resources was firstly in France and Spain in 16th century but they have been spread worldwide. However, the conservation groups worldwide are pushing the restriction on whaling as unrestricted whaling can lead to complete extinction of the whale species from the Earth.
