In a plant that has red flowers, red flower color, rr, is completely dominant to white flower color, rr. if the plant is heterozygous for flower color, which alleles will be carried by the gametes it produces?

If R (capital) is the dominant (red) allele to r (lowercase) allele (white) for flower color. Then the heterozygous will be one of each, or Rr.
Therefore half of its gametes will carry the R for red, and the other half of its gametes will carry the r for white color.

The zone your looking for is the intertidal zone.