Practise Questions

Question 1

Explain how giraffes evolved to have long necks.

Answer 1

giraffe ancestors with slightly longer necks had a better chance of survival and reproduction because they could reach food higher in trees, two long necked giraffes make a baby which has a long neck and so on.

Question 2

Explain how the population of peppered moths changed over time
during the Industrial Revolution.

Answer 2

coal fires had caused sooty air pollution, which had blackened urban tree trunks and walls. So, it stained some if the peppered moths and these moths reproduced and made more black moth.

Question 3

Describe the three main types of rocks and explain how each
type is formed.

Answer 3

3 main types of rocks:

• Igneous rocks are formed from melted rock deep inside the Earth.
• sedimentary rocks are formed from layers of sand, dead plants, and animal skeletons.
• Metamorphic rocks formed from other rocks that are changed by heat and pressure underground.

Question 4

Describe how you can change the strength of an
electromagnet.

Explain why these changes affect the strength.

Answer 4

By increasing the number of turns of the coil.

This strengthens the magnetic field around the coil.