I think you wrote this wrong? Is it not round rr vs wrinkled RR?? I'll answer it with that assumption:
You are crossing a rr with an RR:
You only get Rr back so they will phenotypically be all wrinkled
If you are crossing rr with an Rr (so a heterozygote wrinkled):
50% will be Rr (wrinkled)
50% will be rr (round)
See my picture for the Punnett Squares for both answers!
I dont know how old Eli is but here are some
ride a bike instead of driving a car
plant trees
slow down on use of water/electricity
Plants manufacture glucose during photosynthesis. Which would be the process that plans use to make food using sunlight.