Complete a Punnett square that shows a test cross for a tall pea plant (RR x rr). Place the plant to be tested at the top of the Punnet Square.

In pea plants, a tall stem is dominant (R) over a short stem (r).
This means the genotype of the tested plant is RR so that one would be on top of the Punnett's square.
The Punnet's square would be as follows: