<em>Answer:</em>
<em>A group of cells working together is defined as a tissue and several tissues working together comprise an organ. ... The heart is used as an example of an organ which is made up from muscle and valve tissue.</em>
<em>Explanation:</em>
Answer:
Rivers start as a small body of water. As it is fed by rain, melting snow and ice, it grows larger and becomes a gully. If the right conditions are met and the gully is fed by more water, it becomes a large body of water - a river.
Explanation:
Rivers usually start as a small body of water, known as a stream, that runs and <u>flows down a mountain or a hill</u>. If the right and optimal conditions are met, <u>rains starts falling and feeds different streams that eventually meet and form an individual and larger body of water known as a large channel or gully</u>.
This body of water <u>grows larger as it continues to be fed by rainwater and snow melting (depending on the location) and becomes a </u><u>river</u>. Once multiple rivers are formed, they empty out into the ocean.
Oxygen is absorbed by the blood in the capillaries that surround the alveoli
A) system. Ecosystem and digestive system
Answer:
It is used by every living cell
Explanation: