8. Why is nitrogen used in fertilizer when there's so much N, in the air? O A. There's relatively little air underground.
O B. Ny is toxic to plants.
O C. It's a macronutrient, while gaseous N is a micronutrient.
O D. Plants can't use N2 from the air.

D. Plants can't use N2 from the air

Explanation:

Plants do not and cannot get their N2 directly from the air. Plants get their N2 through a cycle called Nitrogen Fixation.

This means plants need the nitrogen in the soil to consume it and get value from said nitrogen.

Hence, D. Plants can't use N2 from the air, is correct.

Hopes This Helps :)

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation:

it also supports my hypothesis. if you rest first you can squeeze the clothespin more times. from the data i collected the average of the eight people concluded exercise makes your muscles more fatigued and less able to squeeze the clothespin compared to resting before squeezing.