I think your question all turn into lowercases, uppercases, and lowercases are important in genetics because it can differentiate between the dominant and recessive forms.
let me explain at least how to calculate the offspring percentage:
for example, you have Rr crossed with another Rr (R for wrinkled peas and r for smooth peas), you just have to match between the four letters, and you will have four possibilities:
R and R
R and r
r and R
r and r
you will have RR, Rr, Rr, and rr
if we convert into percentages, it will give:
25% RR
50% Rr (there's two Rr so 25 + 25)
25% rr
The correct answer is - A. A few centimeters a year.
Earth's crustal plates move very slowly, between 2 cm and 5 cm (depending on the plate) annually. This is the reason why it takes millions of years for them to significantly change their position, and with it the appearance of our planet. These crustal plates are slowly moving around the planet because they are powered by flow in the interior mantle.