Ecosystem MCQs for NEET — Botany Questions with Answers

Heterotrophs are organisms that cannot produce their own food and rely on consuming other organisms for energy. Decomposition is a process carried out by heterotrophs (like bacteria and fungi) to break down dead organic matter into simpler substances, making nutrients available for other organisms in the ecosystem.

Mycorrhiza refers to a symbiotic association between the roots of a plant and fungi. In this relationship, the fungi help the plant with the absorption of water and nutrients, while the plant provides the fungi with carbohydrates produced through photosynthesis. Hence, the correct option is 'Root + Fungi = Symbiotic'.

Carbohydrates are essential biomolecules that act as a key energy source for all living organisms. They serve as a major component for immediate energy and are involved in various cellular functions.

Decomposers break down dead organic matter and release nutrients back into the soil. These nutrients are then absorbed by plants (producers) for their growth and development.

A cave is considered an incomplete ecosystem because it lacks certain components required for a fully functioning ecosystem, such as producers (plants) that can photosynthesize and produce energy from sunlight. The other options—grassland, river, and wetland—have all the components of a complete ecosystem, including producers, consumers, and decomposers.

Humans are omnivores, which means they consume both plant and animal matter. This is evident from the diverse human diet that includes fruits, vegetables, meat, and dairy products. Being omnivores allows humans to obtain a variety of nutrients necessary for survival.

The given example represents a detritivorous food chain. In this type of food chain, energy is transferred from dead organic matter (detritus) to detritivores like insect scavengers, which are then consumed by higher trophic levels like frogs and snakes. This is different from a grazing food chain, where energy flow starts from living plants (producers) to herbivores (primary consumers).

The smallest dicotyledonous parasitic plant in the world is Arceuthobium minutissimum. This plant is a dwarf mistletoe and is known for its very small size and parasitic nature. It primarily infects coniferous trees.

Viscum, commonly known as mistletoe, is a partial stem parasite. It attaches to the host tree, penetrates its tissues, and extracts water and nutrients. However, it also performs photosynthesis, hence it is not a total parasite.