Question

multiple select question
select all that apply
prior to the 20th century, the two main ideas that provided the basis for most thinking about heredity were ______.

traits are transmitted directly from parents to offspring
traits in offspring are different from parents
heredity occurs only in families
heredity occurs within species

Explanation:

Prior to the 20th century, key pre-Mendelian/heredity theory ideas included direct trait transmission from parents to offspring (e.g., blending inheritance concepts) and the understanding that heredity operates within species (since cross-species inheritance was not widely accepted). The other options are incorrect: offspring traits often show similarity to parents, and heredity is not limited to "families" in a narrow sense but species-wide.

Answer:

traits are transmitted directly from parents to offspring, heredity occurs within species