They provide information about the pasts of the animal and plants.
Answer:
A. Integumentary system
Explanation:
The integumentary system consists of the skin,hair and nail. This system consists of the largest organ in the body. The skin helps in protection against pathogens by shielding the internal body system from external objects.
The skin also helps in Vitamin D production through sunlight.
It also helps to prevent dehydration through regulation of water loss.
There is no element with one valence electron and six energy levels. Only two valence electrons and six energy levels.
Answer:
Calcium
Explanation:
A: Calcium is a group 2 element with two valence electrons. Therefore, it is very reactive and gives up electrons in chemical reactions. It is likely to react with an element with six valence electrons that “wants” to gain two electrons. This would be an element in group 6, such as oxygen.
Answer:
Photosynthesis and cellular respiration allow the carbon and oxygen that organisms consume and produce to be cycled through the ecosystem. They work together so that what is made from one process is used in the other. Without them the ecosystem would run out of carbon dioxide and oxygen, and everything would die.
Drastic change in pH or temperature because the enzyme reaction may become denatured.