Why is that in certain plants deficiency symptoms appear first in younger parts of the plant while in others they do so in mature organs?

Roots developed from parts of the plant other than radicle are called

Name at least five different deficiency symptoms in plants. Describe them and correlate them with the concerned mineral deficiency.

Why do plants don't have respiratory organs ?

Minerals absorbed by the roots travel up the xylem. How do they reach the parts where they are needed most ? Do all the parts of the plant get the same amount of the minerals ?