Answer:
(a)
Decomposers are of two types detritivores and saprotrophs based on how they decompose organic matter. Detritivores. These organisms ingest the dead organic matter and digest and break it down internally into simple nutrients. Earthworms and dung beetles are examples of detritivores. An association between two organisms, in which one is benefited at the cost of the other, is called parasitism.
(b)
There are two types of parasitic plants – Partial parasites and Total parasites. Partial parasites. Some parasitic plants are photosynthetic and depend on the host only for water and minerals. Such plants are called partial parasites or hemiparasites. Mistletoe is an example of a partial parasite. Total parasites – Some other parasitic plants depend completely on the host for sugar, minerals, and water. Such plants are termed total parasites. Cuscuta dodder or Amarvel is a typical example of a total parasitic plant. It can be identified by thin stems appearing leafless, with the leaves reduced to minute scales.
(c)
Many plants absorb soluble nitrogenous substances either nitrate ions or ammonium ions from the soil.