Which of the following statements are incorrect?

Amensalism is a relationship in which one species is unaffected, while the other is benefitted.

The correct answer is Option (2)-Amensalism is a relationship in which one species is unaffected, while the other is benefitted.

 (1) A host is an organism that provides food and shelter to another organism. This statement is correct. In various ecological relationships, a host is indeed an organism that provides resources such as food, shelter, or a habitat for another organism. For example, in parasitic relationships, the host organism provides nutrients and a place for the parasite to live.

(2) Amensalism is a relationship in which one species is benefited, whereas the other is unaffected. This statement is incorrect. Amensalism refers to a relationship where one species is harmed or negatively impacted, while the other is unaffected.

(3) A predator is an organism that catches and kills other organisms for food. This statement is correct. A predator is an organism that hunts, captures, and kills other organisms, typically for food. Predators are part of a food chain or food web and play a crucial role in controlling the population of their prey species.

(4) Parasites that feed on the external surface of the host organism are called ectoparasites. Ectoparasites are parasites that live on the external surface of their host organism. They typically attach themselves to the host's skin, feathers, fur, or scales to obtain nutrients and resources. Examples of  ectoparasites include ticks, fleas, lice, and some mites.