Which of the following is most commonly cited as a predator?

Identify the type of population interaction in which both interacting species benefit.

Which of the following definitions is most appropriate for competition?

Definition / Explanation: Ectoparasites

Study the following four statements $(1-4)$ and select the two which are correct:
$(1)$ Lion eating deer and sparrow feeding on grain are ecologically similar in being consumers.
$(2)$ The predator starfish $Pisaster$ helps in maintaining species diversity of some invertebrates.
$(3)$ Predators often lead to the extinction of prey species.
$(4)$ Production of chemicals such as nicotine and strychnine by plants is a metabolic disorder.
Which two statements are correct?

Discuss the various types of positive interactions between species.