In the family tree shown below, both P and Q are carriers of a recessive allele which causes a condition. Only individuals R and X have the condition. What is…

Which of the following ionic equations are correct?1 X+ e- → X2 X- e- → X3 O2- + 2e- → O4 O2- - e- → O25 2I- 2e- → I6…

Signals are transmitted from one neuron to the next neuron, by molecules. These statements are about this process: 1 Transmitter molecules are formed in the receptors.2 The signal is transmitted…

The mean time for running a race by a group of 20 people was 54 seconds. The times for a second group of people were added and the value of…

When radioactive isotopes decay, they sometimes have to go through a succession of disintegrations to reach a stable isotope. These are called decay chains, and involve the successive emission of…

Which two of the following are produced by the complete combustion of fuels? 1 CH42 CO3 CO24 H2O5 He6 NH3 Answer: 10) D Be careful! It specifies “complete combustion of fuels”.…

Which one of the following correctly completes the statement: During the process of evolution, natural selection will favour individuals with… Answer: 9) B A – WrongA gene pool consists of…

A children's game is played on a square grid starting in the centre. Players spin two spinners to decide how to move their counters. The first spinner decides the direction…