$17.$ The process of converting atmospheric nitrogen to ammonia is known as:

$-$ A$)$ Nitrogen fixation

$-$ B$)$ Nitrification

$-$ C$)$ Denitrification

$-$ D$)$ Ammonification

$18.$ Which of the following is not a direct product of the Haber$-$Bosch process?

$-$ A$)$ Nitric Acid

$-$ B$)$ Ammonia

$-$ C$)$ Hydrogen

$-$ D$)$ Nitrogen

$19.$ Phosphate fertilizers are primarily used to improve:

$-$ A$)$ Soil structure

$-$ B$)$ Water retention

$-$ C$)$ Root development

$-$ D$)$ Pest resistance

$20.$ The use of ammonium$-$based fertilizers can lead to soil:

$-$ A$)$ Alkalization

$-$ B$)$ Acidification

$-$ C$)$ Compaction

$-$ D$)$ Salinization