I think the answer is evolution.
Answer:
its a compound
Explanation:
because it was broken down into a gas and blue powder, elements cant be broken into simpler substances.
Answer:
Symbiosis is a close relationship between two species in which at least one species benefits. Mutualism is a symbiotic relationship in which both species benefit. Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected.
Vein because they have valves to prevent back flow of blood.
<h2>Answer:</h2>
Mesosphere
<h2>Explanation:</h2>
The atmospheric layer that protects the Earth against danger of the rocks is the mesosphere. This layer is above the stratosphere. The temperature drops in this layer to about -100 degrees Celsius. This is the coldest region of the atmosphere. The mesosphere burns up most meteors and asteroids before they are able to reach the earth's surface. It becomes cold enough to freeze water vapor in its atmosphere into ice clouds.
