The physical conditions of the learner are those that belong to the body itself: its state of energy, its health, its maturity and the efficiency of its sense organs. Each of these alters how long and how well a child can attend to a task, so each has a direct bearing on how much is learnt.

Weariness lowers attention, slows reaction and brings errors, so practice beyond a point gives diminishing returns. Ill health keeps a child absent, weak and inattentive. Maturity decides what a child is ready to grasp at all, since a task far above the present level of growth cannot be mastered however well it is taught.

The remaining choice is of a different kind. Treating boys and girls unequally is a social attitude of the people around the learner, not a condition of the learner's own body. It can certainly restrict opportunity, yet as a physical factor it has the least bearing on the capacity to learn.

Gender discrimination option is correct.