# 4-mark practice questions — Pearson Edexcel International GCSE Biology (4BI1)

> 134 questions · biology

## How to answer

4-mark questions are the shortest levels-of-response band. Aim for four scientific ideas, each in its own short sentence.

## Sample questions

1. [Describe the role of nitrifying bacteria and denitrifying bacteria in the nitrogen cycle.](https://www.gradenine.co.uk/q/describe-the-role-of-nitrifying-bacteria-02f69307)
2. [Describe the roles of the sensory neurone, relay neurone and motor neurone in carrying a nerve impulse during a reflex a…](https://www.gradenine.co.uk/q/describe-the-roles-of-the-sensory-0509a409)
3. [Explain why oxygen moves from the air in the alveoli into the blood in the surrounding capillaries during gas exchange i…](https://www.gradenine.co.uk/q/explain-why-oxygen-moves-from-the-0700a3ac)
4. [Describe the role of stomata and the spongy mesophyll layer in gas exchange in a flowering plant.](https://www.gradenine.co.uk/q/describe-the-role-of-stomata-and-0c176178)
5. [Describe the role of xylem vessels in the transport of water through a flowering plant, including the features of xylem …](https://www.gradenine.co.uk/q/describe-the-role-of-xylem-vessels-10551e2e)
6. [Muscle is a tissue found in the wall of the stomach. The stomach works together with other organs such as the pancreas a…](https://www.gradenine.co.uk/q/muscle-is-a-tissue-found-in-10cd647b)
7. [Describe the functions of the nucleus, mitochondria, ribosomes and cell membrane in a eukaryotic cell.](https://www.gradenine.co.uk/q/describe-the-functions-of-the-nucleus-10f3eec1)
8. [Describe the process of eutrophication and explain how it leads to a reduction in the number of animal species living in…](https://www.gradenine.co.uk/q/describe-the-process-of-eutrophication-and-12bf6c6b)

## Related

- [Pearson Edexcel International GCSE Biology (4BI1) revision notes](https://www.gradenine.co.uk/learn/pearson-edexcel-international-gcse-biology-4bi1)
- [Pearson Edexcel International GCSE Biology (4BI1) past papers](https://www.gradenine.co.uk/past-papers/pearson-edexcel-international-gcse-biology-4bi1)
- [Practise with AI marking (free)](https://www.gradenine.co.uk/start)