Answer:
(A) nitrates—proteins
Note: The question is not complete. The complete question is given below:
Which combination correctly pairs a product from a reaction in the nitrogen cycle with a molecule
synthesized by plants using that product?
(A) nitrates—proteins
(B) ammonia—carbohydrates
(C) nitrogenous wastes—nitrites
(D) atmospheric nitrogen—nitrates
(E) atmospheric nitrogen—ammonia
Step-by-step explanation:
The nitrogen cycle refers to the cycle through which nitrogen is transferred for use through both living and non-living things, involving the atmosphere, soil, water, plants, animals and bacteria.
The nitrogen cycle is especially important for living things because nitrogen is essential for the formation of amino acids which form proteins.
The nitrogen cycle occurs in five stages:
1. Nitrogen fixation - Nitrogen gas from the air is converted to nitrate compounds by nitrogen-fixing bacteria in soil or root nodules. Lightning also converts nitrogen gas to nitrate compounds.
2. Nitrification - Ammonia is converted to nitrates by nitrifying bacteria in the soil.
3. Assimilation - Plants absorb nitrates from the soil and use them to make proteins. The plant is then eaten by an animal and are used to produce animal protein.
4. Ammonification- Decomposers break down the bodies of dead organisms, urine and faeces converting them to ammonia in the soil, which is then converted to nitrates by nitrifying bacteria.
5. Denitrification - Denitrifying bacteria in the soil break down nitrates and return nitrogen back to the air.
From the above stages and the options provided, the correct option is A - nitrates from the nitrogen cycle is converted to protein by plants.