Question

order the nitrogenous compounds from most toxic (1) to least toxic (3). ammonia nitrate nitrite

Explanation:

Step1: Recall Toxicity of Compounds

Ammonia ($\ce{NH3}$) is highly toxic to aquatic life and organisms. Nitrite ($\ce{NO2^-}$) is less toxic than ammonia but more toxic than nitrate. Nitrate ($\ce{NO3^-}$) is the least toxic among these three nitrogenous compounds.

Step2: Order from Most to Least Toxic

Most toxic: Ammonia (1), then Nitrite (2), then Nitrate (3). So the order in the boxes (top to bottom or first to last box) should be Ammonia, Nitrite, Nitrate.

Answer:

First box: Ammonia, Second box: Nitrite, Third box: Nitrate (Order from most toxic (1) to least toxic (3) is Ammonia (1), Nitrite (2), Nitrate (3))