Three of the following four are alike in a certain way. Choose the odd one out.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Malaria
Group the diseases by the kind of microorganism that causes them.
Option (1) Polio — caused by a virus.
Option (2) Chickenpox — caused by a virus.
Option (3) Mumps — caused by a virus.
Option (4) Malaria — caused by a protozoan, Plasmodium, spread by the female Anopheles mosquito.
Polio, chickenpox and mumps are viral diseases; malaria is caused by a protozoan, so it is the odd one out.