CBSE Class 7 Answered

Parasitic nutrition or parasitism is a mode of heterotrophic nutrition where an organism (known as a parasite) lives on the body surface or inside the body of another living organism (known as a host). The parasite obtains nutrition directly from the body of the host. Since these parasites derive their nourishment from their host, this symbiotic interaction is often harmful to the host. Parasites are dependent on their host for survival since the host provides nutrition and protection. E.g. Venus fly trap.

Symbiotic relationship or symbiosis is a mutually beneficial association existing between two organisms in which both the organisms derive benefit from each other without causing any harm to each other. E.g. leguminous plants show symbiotic mode of nutrition. Alga and fungus live together. Fungus provides water and shelter to the alga. In return, alga provides food prepared by photosynthesis.