The answer is a “rises because it is less dense than cold air”
Answer:
a sense organ
Explanation:
this is because sense organs are part of nervous system
Answer:
See the answer below
Explanation:
Person X is feeling a burning sensation in several muscles<u> because of the accumulation of lactic acid due to inadequate oxygen in their system.</u> When oxygen becomes inadequate during exercises, anaerobic respiration takes place to augment the oxygen shortage and this leads to the production of lactic acid which accumulates up in the muscles and gives a burning sensation.

Person Y does not feel any burning sensation in their muscles <u>because oxygen is adequate in their system and they do not need to respire anaerobically.</u> <em>Person X exercise regime must have been more rigorous than that of person Y.</em>
Acetylcholine (ACh)
Acetylcholine is an organic chemical that functions in the brain and body of many types of animals as a neurotransmitter.