You cross two true breeding lines of petunia. One produces red flowers and the other white flowers. The F1 offspring all show pink flowers. You conclude from this that:

If you look at a blood sample from a person who is heterozygous at the sickle cell locus you will see both normal circular red blood cells and sickle-shaped red blood cells. This is an example of

A gene for the MN blood group has codominant alleles M and N. If both children in a family are of blood type M, which of the following situations is possible?

The number of different alleles for ABO blood types is _____ resulting in _____ different blood types.