Which of the following is an ectoparasite?

If the '$+$' sign is used for a beneficial interaction,the '$-$' sign for a detrimental interaction,and the '$0$' sign for a neutral interaction,then which population interaction is represented by '$+$' and '$-$'?

What type of relationship is observed between insect-pollinated plants and their pollinators?

Given below are two statements:
Statement $I:$ Gause's 'Competitive Exclusion Principle' states that two closely related species competing for the same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually.
Statement $II:$ In general,carnivores are more adversely affected by competition than herbivores.
In the light of the above statements,choose the correct answer from the options given below:

In an association of two animal species,one is a termite which feeds on wood and the other is a protozoan $Trichonympha$ present in the gut of the termite. What type of association do they establish?

What is the type of interaction between a sucker fish (Remora) and a shark?