Autotrophs, heterotrophs and decomposers are associated with

Step 1: Analyze the question The question asks which concept groups together autotrophs, heterotrophs and decomposers.

Step 2: Explain the concepts

• Autotrophs (producers): organisms that make their own food, usually through photosynthesis, e.g. green plants and algae.
• Heterotrophs (consumers): organisms that depend on other organisms for food, e.g. herbivores, carnivores and omnivores.
• Decomposers: organisms that break down dead plants and animals and return nutrients to the soil, e.g. bacteria and fungi.

These three groups are the biotic (living) components of a system in which energy flows and nutrients cycle. They interact with one another and with non-living (abiotic) factors such as soil, water, air and sunlight. Such an interacting community of living things and its physical environment is called an ecosystem.

Step 3: Check each option

• A. Vegetation: This refers only to plant cover. It does not include consumers or decomposers as a functional system.
• B. Climate: This is the long-term weather pattern. It is not a biological grouping.
• C. Ecosystem: Correct. Producers, consumers and decomposers are its main functional components, linked by food chains and nutrient cycles.
• D. Geology: This is the study of rocks and the Earth's structure, so it is unrelated.

Step 4: Answer The correct option is C. Ecosystem.

Exam tip: Whenever you see producers, consumers and decomposers together, think "ecosystem". Remember the chain: Sun → Autotrophs → Heterotrophs → Decomposers, with nutrients returning to the soil.