In a monohybrid cross, if the gene for tall (t) plants was incompletely dominant over the gene for short (t) plants, what would be the predicted result of crossing two intermediate (tt) parent plants? (hint: you may want to complete a punnett square.)

25 percent tall, 50 percent intermediate, 25 percent short

50 percent tall, 25 percent intermediate, 25 percent short

100 percent intermediate

25 percent tall, 75 percent intermediate

The answer is 25 percent tall, 50 percent intermediate, 25 percent short.

So, we know:
TT - tall plant
Tt - intermediate plant
tt - short plant

After crossing two intermediate plant Tt, each can give either T allele or t allele to the offspring (take a look at the uploaded image with Punnett square):
Parents:               Tt    x    Tt
Offspring:      TT    Tt    Tt     tt

So:
1 of 4 offspring will be tall (TT): 1/4 = 0.25 = 25%
2 of 4 offspring will be intermediate (Tt): 2/4 = 1/2 = 0.5 = 50%
1 of 4 offspring will be short (tt): 1/4 = 0.25 = 25%