The five main external factors that must be present or provided t sustain life are:
1. Water
2. Oxygen
3. Food
4. Atmospheric temperature
5. Atmospheric pressure
<span>The human body needs water, food and oxygen in order the body functions to work properly.
</span>Not every temperature is temperature at which the human can live. For example: we can not stay alive long period of time at temperature of 60 degrees Celsius.
Answer:
Troponin and calcium ions.
Explanation:
Troponin is a component of thin filament along with tropomyosin and actin. It is a protein complex to which calcium binds and start the production of muscular force.
Calcium also playing a very important role in muscle contractions, it binds with troponin and helping to move tropomyosin.
When calcium ion attached to troponin, then conformational changes occurs in troponin shape and moves which allow tropomyosin going away from its inhibitory position from the myosin-binding sites on actin. After this, the energized myosin head starts binding to the actin molecules and starts the cross bridge cycle, which helping in shortening the muscle's fiber.
Firstly they are not membranes and they are villi's which increase the surface area during digestion
The answer is, cellular respiration. I hope I helped!
