Figure 7 shows the world human population from 1800 to 2015 - Edexcel - GCSE Biology - Question 4 - 2020 - Paper 1

The laboratory test for protein typically involves the following steps:

1. Add Biuret Reagent: Introduce Biuret reagent to the sample containing the protein. This reagent usually contains sodium hydroxide and copper sulfate.

2. Observe Color Change: After mixing, observe for a color change. A positive result will show a color change from blue to mauve or purple if proteins are present.

Using Figure 8, we note the mass of meat eaten in 2010 is 275 million tonnes, and in 2000 it is 225 million tonnes.

1. Calculate the Increase: $ext{Increase} = 275 - 225 = 50 ext{ million tonnes}$

2. Calculate the Rate of Increase per Year: With a time span of 10 years: ext{Rate} = rac{50 ext{ million tonnes}}{10 ext{ years}} = 5 ext{ million tonnes per year}

Thus, the rate of increase in the mass of meat eaten is 5 million tonnes per year.

The area labelled cattle is smaller than the area labelled plants because:

1. Energy Transfer: There is less energy in the cattle compared to the plants due to the loss of energy at each trophic level.

2. Energy Usage: Not all the energy from plants is converted into cattle; some energy is lost through respiration and metabolic processes.

3. Consumption Rate: Plants are consumed at a higher rate and provide more biomass compared to the amount converted into cattle.

A large increase in meat consumption may lead to decreased food security due to several interconnected factors:

1. Resource Allocation: More land is required for livestock farming than for arable farming, which means less food is available for direct human consumption.

2. Food Availability: If more meat is produced, it means fewer crops are grown for human consumption, which can lead to shortages in staple foods.

3. Impact on Diet: A heavy reliance on meat can raise health concerns, potentially leading to diet-related diseases that further affect human productivity and resource use.