Questions: The was an early and incorrect idea that the inherited characteristics of offspring are intermediate between maternal and paternal genetic characteristics.

The answer is the second one: blending theory.

Explanation for each option:

1. Intelligent design theory: This is a concept that suggests certain features of the universe and living things are best explained by an intelligent cause, not an undirected process such as natural selection. It is not related to the idea of inherited characteristics being intermediate.

2. Blending theory: This was an early hypothesis in genetics that proposed offspring are a blend, or average, of their parents' traits. It suggested that genetic material from the parents mixes in a way similar to how paints blend. This theory was later disproven by Mendelian genetics, which showed that inheritance is based on discrete units (genes) rather than blending.

3. Synthetic theory of evolution: Also known as the modern synthesis, this theory combines Darwin's theory of natural selection with Mendelian genetics. It does not propose that offspring are intermediate between parental traits.

4. Theory of the mind: This is a concept in psychology that refers to the ability to attribute mental states—beliefs, intents, desires, emotions, knowledge—to oneself and others. It is unrelated to genetic inheritance.

In summary, the blending theory was the early and incorrect idea that offspring's inherited characteristics are intermediate between maternal and paternal genetic characteristics.