Explain why two 16 year-old males of the same weight might need different amounts of energy. (ii) Which two types of nutrient provide most of the energy in our diet?

(b) (i) Calculate the difference in the recommended daily intake of calcium for a 15 year-old male and a 30 year-old male.

A fault is formed in the Earth’s crust as a brittle response to stress. Generally, the movement of the tectonic plates provides stress, and rocks at the surface break in response to this. If you whack a hand-sample sized piece of rock with a hammer, the cracks and breakages you make are faults. An earthquake is caused by a sudden slip on a fault, much like what happens when you snap your fingers. Stresses in the Earth’s outer layer push the sides of the fault together. The friction across the surface of the fault holds the rocks together so they do not slip immediately when pushed sideways.