Ask mr Brain...all will be explained

Why are grandparents called 'great' instead of one, two, three or next? This 'great' tradition started in France in the 16th century. John Calvin, a French religious reformer, used the term in his writings.

His translator used this phrase in an English version of one of Calvin's books, referring to 'his great graunde graunde father'.

Why is cyanide toxic and how does it kill people? It kills by starving body cells of oxygen.

Cyanide competes with oxygen in body cells. The enzyme responsible for using oxygen is more drawn to cyanide than to oxygen.

The presence of cyanide starves a cell of oxygen.

Cells use the oxygen in a complex process to break down sugars to produce energy for vital cell functions.