Which of the following is an observation or inference on which natural selection is based? (A) Individuals do not vary in their heritable characteristics. (B) Only well-adapted individuals produce offspring. (C) Species produce more offspring than the environment can support. (D) Nearly all of each individual's offspring will survive and reproduce.

Verified step by step guidance

1. Identify the key terms in the question: observation, inference, natural selection.
2. Understand the difference between observation and inference: Observation is the act of noting or perceiving objects or events using the senses, while inference is a conclusion or deduction that is made based on observations.
3. Relate each option to the principles of natural selection: Natural selection is based on the observations that individuals in a population vary in their traits, more offspring are produced than can survive, and only some will survive and reproduce based on their advantageous traits.
4. Evaluate each option: (A) is incorrect as it contradicts the observation that individuals vary in heritable characteristics. (B) is an inference, suggesting a consequence of natural selection. (D) is incorrect as it contradicts the observation that not all offspring survive to reproduce.
5. Conclude that (C) 'Species produce more offspring than the environment can support' is an observation on which natural selection is based, as it directly relates to the struggle for existence, a key component of Darwin's theory of natural selection.