Answer:
Some bacteria like <em><u>rhizobium</u></em> and <u><em>blue green algae</em></u> are able to fix nitrogen gas from the atmosphere to enrich the soil with nitrogen compounds and increase its fertility. The nitrogen-fixing bacteria and blue green algae are called <u><em>biological nitrogen fixers.</em></u>
There are 0.25 kilometers in 250 meters
Explanation: C) the air temp. at the top is lower
Because the resulting hybridized orbitals are more stable