Which of the following represents the correct pair of organisms and their type of interaction?

Cattle or goats are never seen browsing on $Calotropis$ growing in abandoned fields because of the presence of:

Competition occurs when

In commensalism,

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?

$A$ : The interaction between sea anemone and clown fish is commensalism.
$R$ : The fish gets protection from predators but anemone does not appear to derive any benefit.