Which of the following is NOT a way in which infectious diseases can be transmitted?

Single-celled organisms do not need a transport system because:

Most plant and animal cells contain:

Which one of the following diagrams illustrates short-sightedness?

(F = Focal point)

An example of an air pollutant is:

Which one of the following taxonomic groups contains the greatest number of organisms?

The length of an insect such as a grasshopper increases in steps.This is because:

All of the following processes result in energy loss from an ecosystem EXCEPT for:

Which one of the following is NOT a receptor in the body?

Which of the following statements about aerobic respiration is correct?

The optimum pH for most enzyme action is:

In a plant, water and dissolved minerals are transported in the:

Malaria is spread by:

In hot conditions the surface blood vessels in the skin undergo vasodilation. This allows:

Plants lose water through their leaves by the process of:

A species of mouse has 32 chromosomes in its muscle cells.What will be the numbers of chromosomes in the mouse′s skin cells and sperm cells?

Which of the following substances contains the elements carbon, hydrogen, oxygen and nitrogen?
Ⅰ DNA
Ⅱ carbohydrates
Ⅲ lipids
Ⅳ proteins

An enzyme which has an optimum pH of 3 will function best in the:

The scientific name of an organism is derived from its:

Cells become specialised to carry out different roles.This process is called: