It is defined as the variability among living organism in the terrestrial, marine, and other aquatic resources of the Earth.

Step 1: Read the question carefully and understand what is being asked.

Step 2: Identify the key information in the question. In this case, the question is asking for the definition of something related to the variability among living organisms in different environments.

Step 3: Analyze the given text to find the answer. The text states that it is defined as the variability among living organisms in the terrestrial, marine, and other aquatic resources of the Earth.

Step 4: Summarize the answer in your own words. Biodiversity is the term used to describe the variability among living organisms in different environments, including terrestrial, marine, and other aquatic resources on Earth.

Step 5: Check your answer for accuracy and clarity. Make sure that your response accurately reflects the information provided in the given text and is clear and understandable.