Measles is a highly infectious viral disease. How is the measles virus spread from one person to another? Select one option:

• Through contaminated drinking water
• By droplets from coughing or sneezing
• By direct contact with open skin wounds

The table below shows the number of new measles cases diagnosed in a specific region.

Describe what happened to the number of new measles cases from 2012 to 2018.

What could cause a significant decrease in the number of new measles cases in the future? Select one option:

• A decrease in the number of public vaccination programs
• A rise in the proportion of the population that is vaccinated
• A higher rate of international travel

Scientists use vaccines to prevent viral diseases like measles. The statements below describe how a vaccine works to protect a person.

• A - Antibodies attach to the inactive virus.
• B - If the active virus enters the body in the future, antibodies are produced very rapidly.
• C - A safe, inactive form of the virus is injected into the body.
• D - White blood cells identify the foreign antigens and produce specific antibodies.

Write the stages A, B, C, and D in the correct sequence to show how vaccination works. The first stage has been completed for you:

$$C\to \underline{}\to \underline{}\to \underline{}$$

Before a vaccine is approved for use, it undergoes rigorous clinical testing. After experimental testing on cells and tissues in a laboratory is complete, what is the next stage in preclinical testing? Select one option:

• Testing on healthy human volunteers
• Testing on live animals
• Testing on patients who are already ill

Some important medicines originated from natural sources like plants and fungi. Match each medicine to the correct source it originally came from:

• Aspirin
• Penicillin

Sources:

• Foxglove plants
• Willow bark
• Penicillium mould
• Tobacco plants