Question

If '+' sign is assigned to beneficial interaction '–' sign to detrimental and '0' sign to neutral interaction, then the population interaction represented by '+' '–' refers to
A. Commensalism
B. Parasitism
C. Mutualism
D. Amensalism

Answer 1

Hint: There are various interactions between animals and plants in nature. They help each other to co-exist either by benefiting or harming each other. This relationship is very specific. It sometimes makes them sensitive to some growths making them indicators for the same. These interactions make the environment.

Complete answer:
Ecosystem is the whole of the species of every kind on our planet Earth. There are units which make this large biome possible. The change in the basic unit will affect all the ranking in the hierarchy thereby, effecting the largest ranking. Ecology is the sum of all the different varieties in our surroundings. The manner in which organisms reside therefore becomes very important to understand.
The ecosystem is made up of many communities spread in larger areas. They all have different characteristics but live in the same atmosphere under the common universe.
When the different species live together, they live in some particular interactions in which one can be benefitted, harmed or can have a neutral effect.
Option A: Commensalism: It is interaction when one is benefited while the other has a neutral affect. Thus it is denoted by +0.
Option B: Parasitism: It is the relationship between two organisms in which a parasite will take its food from the host. The host is harmed and the parasite is benefitted. So it is represented by + -.
Option C: Mutualism: This interaction involves benefitting both the organisms by mutually helping each other. It gives the ++ interaction.
Option D: Amensalism: It refers to the interaction when one organism is harmed while the other has a neutral effect. Thus it -0 interaction.

So, the answer is option B: Parasitism.

Note:
Symbiotic relationship is when two organisms interact with each other in such a way that either one or both of them are benefitted.
Azolla is used as animal feed and water purifier. It is used in biogas production. It can be supplied with the fertilizers. Anabaena lives in a symbiotic relationship with Azolla. Azolla is a fern. It provides the Anabaena with a safe environment for nitrogen exchange.