Identify the correct statements regarding Mass flow hypothesis.

(A) Mass flow is faster than diffusion.

(B) Mass flow is the result of pressure difference between the end points.

(C) Different substances involved in mass flow move at different paces.

(D) Mass flow can result through either a positive or a negative hydrostatic pressure gradient.

Choose the correct answer from the options given below :

During symport two different molecules move across the membrane :

Given below are two statements :

Statement I : The process of translocation through phloem is unidirectional but through xylem, it is bidirectional.

Statement II : The most readily mobilized elements are phosphorus, sulphur, nitrogen and potassium.

In the light of the above statements, choose the most appropriate answer from the options given below :

Movement and accumulation of ions across a membrane against their concentration gradient can be explained by