While explaining interspecific interaction of population,$(+)$ sign is assigned for beneficial interaction,$(-)$ sign is assigned for detrimental interaction and $(0)$ for neutral interaction. Which of the following interactions can be assigned $(+)$ for one species and $(-)$ for another species involved in the interaction?

Define/Explain: Endoparasites.

Which of the following is a correct pair?

Choose the correct option for population interaction.

Which of the following is an example of a positive interaction in a population?

The orchid $Ophrys$ employs 'sexual deceit' to get pollinated by a species of bee. One petal of its flower bears an uncanny resemblance to the female of the bee in size,colour,and markings. The male bee perceives it as the female and attempts to copulate with the flower. During this process,pollen grains are dusted on the male bee's body. What is this phenomenon called?