A.ans=A food chain is systematic hierarchical series that shows the sequential dependence of organisms on each other for food.

Trophic level refers to the hierarchical levels in an ecosystem or a food chain. It contains organisms that share the same function in a food chain and have similar nutritional relationship with the producers (primary source of energy).

The first trophic level in a food chain is occupied by the producers. These are the primary source of energy in a food chain.

The second trophic level in a food chain is occupied by the herbivores. These organisms feed directly on the producers. They are referred to as primary consumers.

Thethird trophic level is occupied by the carnivores.These organisms feed on the herbivores (second trophic organims). In the third trophic level are carnivores that only feed on the herbivores. They are referred to as secondary consumers.

The fourth trophic level is occupied by carnivores that feed on other carnivores. These carnivores are referred to as tertiary consumers.

The fifth trophic level is occupied by occupied by organism such as bacteria and fungi that decompose all other dead organisms.

Note: omnivores are animals that feed on both herbivores and producers (and at times carnivores as well). They can fall on fall on either the second, third or forth trophic level.

A.ans= Each livingbeing within a food chain can be categorized by tropic level. There are4 tropical levels:

1. Primaryproducers

2. Primaryconsumers

3. Secondaryconsumers

4. Tertiaryand other high-level consumers

Secondaryconsumers are carnivores . They eat herbivores which are knownas the primary consumers

B.ans=Nutrientcycles occur withinecosystems.Ecosystemsare interconnected systems where matter and energyflowsand is exchanged as organisms feed, digest, and migrate about. Minerals andnutrientsaccumulate in varied densities and uneven configurations across the planet.

B.ans=Anutrient cycle(orecological recycling) is the movement and exchange oforganicandinorganicmatter back into theproductionof living matter. The process is regulated byfood webpathways thatdecomposematter intomineral nutrients. Nutrient cycles occur within ecosystems. Ecosystems are interconnected systems where matter and energy flows and is exchanged as organisms feed, digest, and migrate about. Minerals and nutrients accumulate in varied densities and uneven configurations across the planet. Ecosystems recycle locally, converting mineral nutrients into the production ofbiomass, and on a larger scale they participate in a global system of inputs and outputs where matter is exchanged and transported through a larger system ofbiogeochemical cycles.

C.ans=Within an ecologicalfood chain,Consumersare categorized intoprimary consumers,secondary consumers, tertiaryconsumers.Primary consumersareherbivores, feeding onplants. Caterpillars, insects, grasshoppers, termites and hummingbirds are all examples ofprimary consumersbecause they only eat autotrophs (plants).