1. Name a group of organisms that break down the dead leaves and release mineral ions into the soil - Edexcel - GCSE Biology Combined Science - Question 1 - 2021 - Paper 1

As light intensity increases, the number of small plants per m² generally increases. This can be attributed to the fact that higher light intensity enhances photosynthesis, leading to better growth and more robust plant populations. In contrast, lower light levels limit photosynthesis, resulting in fewer plants.

One variable the scientist should have controlled is the same time of day for all light intensity measurements. This ensures that the light conditions are consistent across different areas.

To investigate the effect of light intensity on the growth of stinging nettles using a belt transect, the scientist should first select a straight line (transect) across the area of interest. Then, along this line, use a tape measure to mark intervals (e.g., every meter) where measurements will be taken. At each interval, the scientist should measure the height and density of stinging nettles and record corresponding light intensity using a light meter placed directly above the plants. This process allows for a comparative analysis of how varying light conditions impact the growth of stinging nettles.