Solution:
Nitrogen is important because, it helps us grow crops, and it produces grass for animal. It comes from lightning and is named nitrogen fixation
By which free nitrogen (N2) is extracted from the atmosphere and converted (fixed) into nitrogen compounds which are plant nutrients (fertilizer). In nature, this process is carried out by certain bacteria (present in the root nodules of legumes such as beans and peas), blue-green algae, and the lightning flash.
Thus the Nitrogen form the atmosphere the biotic part to the ecosystem converted into the biotic part.
I would say D! Purely because it is looking at the effects of humans (therefore related to topics more geographical).
Hope that helps. :)
Light that passes through a polarizing filter is called a vacuum.
<h2>
Biennial plants</h2>
Explanation:
This plant is a biennial, which means it will just take longer than a season to mature enough to produce flowers.
Since the Sweet William plant did not flower last year when it was planted and this year also it did not bud till the spring. So, we can assume that these plant will need atleast two seasons to mature hence they are biennials.
Depending on the life span, plants are classified as annuals (one season), biennials(two season) and perennials (more than two years).
