Answer:
a
Explanation:
it clear and short enough for kids
It is called a double circulatory system because blood passes through the heart twice per circuit. The right pump sends deoxygenated blood to the lungs where it becomes oxygenated and returns back to the heart.
Answer:
lithosphere
Explanation:
process of elimination
mesosphere is past where planes fly, inner/outer core are towards the center of the earth
Answer:
D. By decreasing the activation energy of a reaction
Explanation:
