Sunlight is the primary source of energy for most ecosystems because it is the energy that plants use to photosynthesize.

Photosynthesis is the process by which plants use sunlight to produce food.

Decomposition is the process by which organisms break down organic matter into simpler substances.

Nutrient cycling is the process by which nutrients are recycled from dead organisms back into the environment.

Decomposers play a vital role in nutrient cycling by breaking down organic matter into simpler substances, releasing nutrients back into the environment, and helping plants absorb nutrients from the soil.

Producers play a vital role in energy flow by producing food from inorganic molecules.

Consumers play a vital role in energy flow by consuming food from other organisms.

Decomposers play a vital role in energy flow by breaking down organic matter into simpler substances.

Producers are the first trophic level in an ecosystem because they produce food from inorganic molecules.

Top predators are the highest trophic level in an ecosystem because they do not have any predators.

Energy flow is the term for the transfer of energy from one trophic level to the next.

Nutrient cycling is the term for the transfer of nutrients from one trophic level to the next.

Nutrient leaching, nutrient runoff, and nutrient volatilization are all processes by which nutrients are lost from an ecosystem.

Nutrient fixation, nutrient deposition, and nutrient weathering are all processes by which nutrients are added to an ecosystem.

Ecosystem equilibrium, ecosystem stability, and ecosystem resilience are all terms for the balance between energy flow and nutrient cycling in an ecosystem.