The breaking down of rocks, minerals, and soils on Earth's surface is known as weathering. Weathering is caused by many agents like temperature, rain, wind, frost, acids, plants (types like herbs, shrubs, and trees), animals, and microbes. Weathering weakens rocks by making them easier to mine.

Symbiosis is the biological interaction between two different organisms belonging to two different species living in a close relationship in which both the partners mutually benefited. An example of symbiosis is Lichens that show mutualism (e.g. sea anemone and clownfish, etc.) between an alga and fungi. The fungal partner is known as mycobiont gives protection to the algal partner. The algal partner is known as phycobiont gives food to the fungal partner.

Predation is a biological interaction between two organisms predator and prey. The predator kills and eats the other organism. It is one of the ecological process by which energy is transferred from one organism to the other organism. Lions are predators that hunt and kill deer which are their prey. Predators camouflage themselves so they can hide. They have sharp claws and jaws for hunting.

The symbiotic relationship between different organisms where one organism called the parasite lives on the other organism called the host. In this type of relationship, the parasite depends on the host for food and shelter. The host gets no benefit from the parasite instead it is harmed by the parasite. Parasites are of different types- ectoparasites, endoparasites, obligate parasites, facultative parasites.

Litter is the undecomposed plant materials like leaves and twigs on the forest floor. It plays a very important role in forest ecosystems by adding fertility to the soil because decomposing litter releases essential nutrients to the soil. Abiotic (e.g. wind, water, soil, temperature, etc.) factors play important role in the decomposition of litter. It increases ecological productivity.