Ace A Level Biology 2026 – Dive Deep and Conquer Science!

Communicable diseases are defined as illnesses that can be transmitted from one organism to another. This transmission can occur through various means, such as direct contact, aerosols, contaminated food and water, or vector-borne routes (like insects). The organisms that can transmit these diseases include bacteria, viruses, fungi, and parasites. Understanding this concept is vital for public health as it highlights the need for measures such as vaccinations, sanitation, and health education to prevent the spread of these diseases in populations.

The other choices either specify a limited scope that does not encompass all communicable diseases (as in the case of diseases affecting only plants or those caused by nutritional deficiencies) or refer to hereditary issues (genetic diseases) that cannot be transmitted between individuals. Thus, the focus on the capability to transfer between hosts makes the correct answer comprehensive and central to the definition of communicable diseases.