In plants,a common symptom caused by the deficiency of $P, K, Ca$ and $Mg$ is the

Deficiency of which element causes deficiency of nitrogen?

On the basis of symptoms of chlorosis in leaves,a student inferred that this was due to the deficiency of nitrogen. This inference could be correct only if yellowing of leaves appeared first in

Premature leaf fall is due to deficiency of

Plants grow in a magnesium-deficient soil,but what happens if urea is added to the soil?

Interveinal chlorosis of leaves is caused by the deficiency of