The protozoan that causes malaria is:

1. Entamoeba histolytica
2. Euglena
3. Paramecium
4. Plasmodium

The chemical substance mainly responsible for tooth disorders is

1. Calcium
2. Chloride
3. Fluorides
4. Iodides

The germ causing Hepatitis is transmitted through:

1. The bite of a mosquito
2. Contamination of food by a housefly
3. Personal contact with a patient
4. Contaminated water

Which of the following is an agent that acts as an intermediate carrier of a pathogen?

1. Genes
2. Water
3. Vector
4. None of these