<span>The answer is nitrogen. Plants cannot use atmospheric nitrogen directly. Nitrogen from the air must be converted into the different form so plants can absorb it. Thus plants need nitrogen-fixing bacteria to convert atmospheric nitrogen into ammonium, which is available for plants to absorb it. </span>
Answer:
I believe the answer is A) energy pyramid
Explanation:
It's talking about trophic levels, as opposed to individual organisms.
Beginning in the mid 1600's Earth entered into a mini-ice age. 1815 was known as the "year without a summer" and snow fell in many European countries during the summer months. The prolonged climate change is attributed to low sun spot activity, while the summer snow is believed to be the result of
A major volcanic eruption.
Cell transport is useful because it's, essentially, the movement of cells across the blood/veins. Active transport uses energy, while passive transport does not.
