Question

during the nitrogen cycle, through which structure are nitrogen compounds first absorbed into the plant?
roots
leaves
flower
stem

Explanation:

Plants absorb nitrogen compounds (such as nitrates) from the soil. The primary plant structure for absorbing substances from the soil is the roots. Leaves are mainly for photosynthesis and gas exchange. Flowers are for reproduction. The stem is for support and transport (but not the first - site of nitrogen compound absorption). So, during the nitrogen cycle, nitrogen compounds are first absorbed into the plant through roots.

Answer:

A. roots