The answer is D, photosynthesis and respiration.
—Evidence—
Oxygen is a byproduct of photosynthesis and, correspondingly, carbon dioxide the byproduct of respiration.
Oxygen gives our cells the ability to break down food in order to get the energy we need to survive. Although other animals may use different organs to breathe with, they all get oxygen into their bodies through respiration.
Earth's atmosphere is 78%<span> nitrogen </span>21%<span> oxygen, </span>0.9%<span> argon, and </span>0.03%<span> carbon dioxide with very small percentages of other elements.
hope it helps</span>
Chromosome is to cactus as gene is to a needle.
Answer:
.I do not have an answer for this
Answer:
Lignin.
Explanation:
The structural integrity of plant spores is lignin that is present in many parts of the plant. This lignin provides hardness to the plant body which help them to stand the plant erect. If this lignin is not present in the plant body the plant will not stand erected. This lignin is present in large amount in the stem of plant body so that's why the lignin provides structural integrity to plant spores