One to four mark questions will start with command words such as 'describe' or 'explain'. Some command words are easy to understand such as:
The command words 'describe' and 'explain' can be confusing. If you are asked to describe a graph, you will be expected to write about its overall shape, whether it is linear or curved, the slope of gradients etc. If you are asked to explain why a pattern or trend is seen in a graph, you will be expected to use your science knowledge, not just say what you see (which is a description), for example, the graph shows a steep linear increase for the first three hours because…
Explain how and why questions often have the word 'because' in their answer. Describe questions don't.
The number of marks per question part is given in this form '[2 marks]'. It is essential that you give two different answers if a question is worth two marks. Sometimes you can gain a second mark by giving the units in a calculation or stating specific data points, eg during the first two years the number of lions deceased by seven.
You will be expected to write in more depth for three and four mark questions. They might ask you about a process such as the carbon cycle or the method you would use in an experiment.
These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.
Describe why Darwin was reluctant to publish his findings when he returned from his voyage to the Galapagos Islands. [2 marks]
What does natural selection mean? [2 marks]
The best adapted organisms in a population are most likely to survive  and reproduce .
What are fossils? [2 marks]
They are the imprints or remains of organisms  which were alive millions of years ago 
Describe how the binomial system is used to name organisms. [2 marks]
Explain why there are gaps in the fossil record. [3 marks]
What observations did Darwin make on the Galapagos Islands that helped him develop his theory of evolution? [4 marks]