What did Gause demonstrate regarding ecology and competition?

Which one of the following population interactions is widely used in medical science for the production of antibiotics?

Which of the following mechanisms helps organisms protect themselves from predators?

Some plants have a habit of harbouring ants to save themselves from damage by other animals,which is known as:

American lakes visiting flamingoes and resident fishes compete for their common food $A$ in the lake. Resources $B$ limiting for competition to occur; in interference competition,the feeding efficiency of one species might be $C$ due to the interfering and inhibitory presence of the other species,even if resources (food and space) are abundant. Choose the correct option for $A$,$B$,and $C$.

Identify the epiphytic organism.