Which observation led Mendel to the idea that parents passed only part of their genes to offspring?
â—‹ A tall plant could transfer alleles for a short plant to the offspring.
â—‹ A short plant always transferred alleles for a tall plant to the offspring.
â—‹A short plant could transfer alleles for a tall plant to the offspring.
○ A tall plant always transferred the alleles for a short plant to the offspring.​