What is hydrotropism? Give one example.

'A' forms the outer portion of the kidney and 'B' form the inner portion of the kidney. Name A and B.

Study the diagram given below and answer the questions that follows.

(a) Name the parts labelled 1, 2 and 3 in the diagram.

(b) Mention the collective terms for the membranes covering the brain.

(c) What is the function of cerebrospinal fluid?

Give differences between passive transport and active transport.