Edexcel IGCSE Biology Biology Paper 2 June 2024 question paper 4BI1/2BR

Suggest why deep sea fishing has a risk of serious injury or death to people. (lines 2 to 3)

Give three reasons why the scientists’ prediction of an increase in ocean fish production to 44 million tonnes by 2050 is only an estimate. (lines 4 to 6)

Explain how fish farms cause pollution. (lines 12 to 16)

Fish farmers use methods to control disease in their fish farms.

Describe the methods a fish farmer could use to reduce the incidence of disease in a fish farm.

Explain how these methods may affect the local ecosystem.

Explain why locating the fish farms further out to sea may help reduce the effects on the local ecosystem. (lines 12 to 16)

Suggest why fish farming further out at sea will be more difficult to monitor and regulate. (lines 14 to 16)

Give a reason why farming fish that are herbivores is an advantage for the fish farmer. (lines 27 and 28)

Explain why small, local freshwater fish farms would have less impact on global warming than large fish farms at sea.

Mammals, such as humans, need to regulate their internal environment.

What is the process that maintains a constant internal environment?

Table 1 shows the water input and output per day for a person in normal temperature conditions.

The water loss from gas exchange plus the loss from sweating are referred to as the insensible water loss. This water loss is called insensible because it cannot be measured directly.

Calculate the percentage of the water loss that is classified as insensible.

This data comes from a person who has a mass of 70 kg.

Assuming the same proportions, calculate the water input from food for a person who has a mass of 110 kg.

input from food =_........ litres

Water loss in faeces is usually relatively low.

Illness such as food poisoning can produce symptoms including vomiting, diarrhoea and a high temperature. These symptoms can change water balance in the body.

Explain how the symptoms of food poisoning can change water balance in the body.

The photograph shows a mammal called a degu.

(Source: © R. Maximiliane / Shutterstock)

A degu is a rodent that lives in a very dry environment in South America. The degu gets its water input by feeding on plants.

The water intake of the degu changes during the winter and summer months.

Table 2 shows the body mass, water intake and urine concentration of the degu in the winter and in the summer. It also shows the total rainfall in winter and in summer.

Comment on the differences in body mass, water intake and urine concentration in winter and summer.

Use the data in the table and your own knowledge in your answer.

The diagram shows a section of human skin with some structures labelled.

Which structure is a pore of a sweat gland?

Which structure carries blood?

The skin responds to changes in temperature.

Describe how the skin responds when a person enters a cold environment.

Scientists investigate the effect of heat strain on two groups of men.

Heat strain is caused by increasing the external temperature.

The scientists measure the skin temperature with no heat strain, low heat strain and moderate heat strain.

They also measure the rate of sweating with low and moderate heat strain.

The table shows the scientists’ results.

Discuss the relationship between age and the effect of heat strain on the mean skin temperature and the mean rate of sweating.

Use information from the table and your own knowledge in your answer.

A teacher investigates gas exchange in different conditions.

They use orange hydrogen-carbonate indicator solution, which changes colour depending upon the concentration of carbon dioxide in the tube.

This is their method.

Step 1 put 5 cm³ of hydrogen-carbonate indicator solution into each of five test tubes A, B, C, D and E

Step 2 place a wire mesh and two green leaves in test tube A

Step 3 set up tubes A to D so that they contain leaves or maggots as shown in the diagrams

Step 4 set up tube E without leaves or maggots

Step 5 place test tubes A, C and E in bright light for two hours

Step 6 place test tubes B and D in the dark for two hours

Step 7 observe the colour of the indicator in each test tube

Test tube A
Test tube B Test tube C
Test tube D Test tube E in light
in dark in light
in dark
in light

indicator solution
indicator solution
indicator solution

State the dependent variable in this investigation.

Give the function of the wire mesh in the test tubes.

State one variable that the teacher has controlled in their investigation.

The table shows the results of this investigation.

Explain the relationship between the test tube contents, the light condition and the colour of the indicator after two hours.

The teacher sets up another test tube that contains leaves and maggots. They put the test tube in the light for two hours.

The colour of the indicator after two hours remains orange.

Explain why the indicator remains orange.

Loss of trees is known as deforestation.

From 2001 to 2021, Russia, Brazil and Canada had the most deforestation.

• Russia lost 76.0 Mha of tree cover. This loss was 10% of forests in Russia. The loss accounted for 17% of the total tree cover lost in the entire world.

• Brazil lost 62.8 Mha of tree cover. This loss was 12% of forests in Brazil. The loss accounted for 14% of the total tree cover loss in the entire world.

• Canada lost 49.3 Mha of tree cover. This loss was 11% of forests in Canada. This loss accounted for 11% of the total tree cover loss in the entire world.

Use this data to determine the total tree cover loss by countries other than Russia, Brazil and Canada from 2001 to 2021.

Calculate the loss of tree cover in Brazil per month from 2001 to 2021.

Give your answer in standard form.

tree cover loss =_........ Mha per month

Explain why Russia contributed 17% of the total tree cover loss in the entire world even though the loss of tree cover in Russia was only 10%.

Describe the effects of deforestation on an ecosystem.

Cells use genetic information when carrying out protein synthesis.

Give the difference between a gene and a genome.

Describe the process of transcription.

Explain why a change in the sequence of bases in the DNA does not always result in a change in enzyme function.

Some characteristics are determined only by the genes, and some are determined by a combination of the genes and the environment.

Give an example of each type of characteristic in humans.

determined only by the genes

determined by the genes and the environment