Understand the definition of a biotic factor: Biotic factors are the living components of an ecosystem, which include all organisms such as plants, animals, fungi, and microorganisms.
Identify the options given in the problem: Sunlight, Plants, Temperature, and Water.
Determine which of these options are living components. Sunlight, temperature, and water are abiotic factors, meaning they are non-living components of an ecosystem.
Recognize that plants are living organisms and thus represent a biotic factor in the ecosystem.
Conclude that among the given options, 'Plants' is the correct example of a biotic factor in an ecosystem.