Question

if you cross homozygous dominant red flower (RR) with a homozygous recessive white flower (rr), what are the possible genotypes and phenotypes of the offspring?

Answer 1

Have you learned how to draw Punnett Squares in class?

So, here we have RR for a RED flower,
and rr for a WHITE flower.

We draw Punnett Squares, to look at how those two flowers would cross one another, when they make offspring. (aka baby flowers)



The capital letters are called "dominant alleles."
In other words, the capital letters are the ones that matter the most.

Take a look at the Punnett Square that I've drawn.

You see how there are four squares?

The letter pairs in each of those four squares are all the possible genotypes and phenotypes of the offspring.

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You see how in three of those squares, there is a capital R?

3 out of 4 is 75%. Yes?

That means that if these two flowers make a baby,
there is a 75% chance that their baby will be a RED flower.

(Remember, the capital letters are the ones that matter, in a trait.)

Do you also see how there's only one square, with rr?

There are no capital letters in that one square.
And if there are no capital letters, THEN the lowercase letter matters.

Again, ONE square has rr.
1 out of 4 is 25%. Yes?

That means that there is a 25% chance that the baby flower will be white, instead of red.