Match the column I and II.

Column I	Column II
A. Parasitism	I. + +
B. Commensalism	II. + -
C. Amensalism	III. 0 +
D. Mutualism	IV. 0 -

The correct option is D

Explanation:
Parasitism:

1. The interaction in which only one species benefits and the interaction is harmful to the other species is called parasitism.
2. This interaction is represented as "+ 0".
3. E.g., Sheep (host) and liver fluke (parasite) in fluke disease in cattle.

Commensalism:

1. The interaction where one species is benefited and the other is unaffected is called commensalism.
2. It is represented as "0 +".
3. E.g., barnacles growing on the back of a whale.
4. They don't harm the whales or feed on the whales, like true parasites do.
5. Barnacles don't serve any obvious advantage to the whales, but they get a place to hang onto the whale without getting washed away by water.
6. Barnacles also find the slow-swimming whale a good ride through nutrient-rich ocean waters.

Amensalism:

1. The interaction where one species is harmed while the other is unaffected is called amensalism.
2. It is represented as "0 -".
3. E.g., Penicillium secretes penicillin which kills bacteria but it has no effect on Penicillium itself.

Mutualism:

1. The interaction in which both the species are benefitted is called mutualism.
2. It is represented as "+ +".
3. E.g., interaction between algae and fungi in lichen and interaction between fungi and roots of gymnosperms in mycorrhiza​.

Final answer: A-II, B-III, C-IV, D-I.