Interaction between organism and their environment, which includes
both biotic and abiotic factors.

Ecology is the study of how organisms interact with one another and with their physical environment. The distribution and abundance of organisms on Earth is shaped by both biotic, living-organism-related, and abiotic, nonliving or physical, factors. biosphere
The broadest, most inclusive level of organization is the biosphere. This includes both biotic and abiotic components of the earth and the part of the atmosphere that supports life. biotic factor is a living thing that has an impact on another population of living things or on the environment. Abiotic factors do the same thing, but they are non-living. Together, biotic and abiotic factors make up an ecosystem. To survive, biotic factors need abiotic factors. Ecology studies the interactions between biotic factors, such as organisms like plants and animals, and abiotic factors. For example, all animals (biotic factors) breathe in oxygen (abiotic factor). All plants (biotic factor) absorb carbon dioxide (abiotic factor) and need water (abiotic factor) to survive. Abiotic factors are the non-living parts of an environment. These include things such as sunlight, temperature, wind, water, soil and naturally occurring events such as storms, fires and volcanic eruptions. Biotic factors are the living parts of an environment, such as plants, animals and micro-organisms. An organism is made up of four levels of organization: cells, tissues, organs, and organ systems. These levels reduce complex anatomical structures into groups; this organization makes the components easier to understand.

The correct answer is c

Very hard to understand