Symbiosis is the term used to describe the interactions between different species within a community, including competition, predation, mutualism, and commensalism.

The sea otter is an example of a keystone species because its presence has a disproportionately large impact on the structure and function of its ecosystem, such as maintaining kelp forests and supporting diverse marine life.

Organic agriculture is a farming practice that emphasizes the use of natural methods, such as crop rotation, composting, and biological pest control, to reduce the reliance on chemical inputs and promote sustainable farming methods.

A food chain is a linear sequence of organisms through which nutrients and energy pass, starting with a producer organism and ending with a top predator.

The mistletoe and oak tree have a mutualistic relationship, where the mistletoe obtains nutrients and water from the oak tree, while the oak tree benefits from the mistletoe's ability to fix nitrogen from the atmosphere.

Evolution is the process by which organisms adapt to their environment over time, resulting in changes in their genetic makeup and traits.

Remoras and sharks have a commensal relationship, where the remoras attach themselves to the shark's body and feed on scraps of food, while the shark gains no benefit or harm from the remora's presence.

Crop rotation is an agricultural practice that involves growing different crops in sequence on the same land to maintain soil fertility, prevent pests and diseases, and improve overall crop yields.

Competition is the process by which organisms compete for limited resources in an ecosystem, such as food, water, and territory.

Tapeworm and human have a parasitic relationship, where the tapeworm lives inside the human's digestive system and obtains nutrients from the human's food, while harming the human's health.

Biomass is the total amount of living matter in an ecosystem, including plants, animals, and microorganisms.

Agroforestry is an agricultural practice that involves the integration of trees and shrubs with crop and livestock production systems to improve soil fertility, provide shade and shelter, and increase biodiversity.

Carrying capacity is the maximum population size that an ecosystem can support, based on the availability of resources such as food, water, and shelter.

Lions and zebras have a predator-prey relationship, where the lions hunt and eat the zebras.

Ecological footprint is the measure of the impact of human activities on the environment, including the amount of land, water, and resources required to sustain a certain population.