Please explain? 10 points best answer!?

Each of the two plants have a set of genes, for this example Blue is dominant, so if any plant has a B, it will be Blue, it has to have a pair of W to be white, since white is recessive. Since you said the plants were purebred this means all we have to worry about is the color of the flowers. To figure this out I suggest making a Punnett square:

In this example the blue parent flower has both B genes, since blue is dominant it could also have BW makeup, which will be in the second example.

................................... Blue Flower
.....................................B ..........B

White.........W.................BW.......BW
Flower
..................W ...............BW........BW

In this example all of the four possibilities are a makeup of BW, and since blue is dominant, 100% of the time the offspring would be blue.

In this example the blue parent flower has a makeup of BW

. Blue Flower
.............................B........W

White .........W......BW....... WW
Flower
....................W.....BW........WW

Here the flower has a 50/50 chance of being either blue or white

So out of the 8 possible answers 6 of them were blue, so 6/8 times it would be blue, so I would say more often, blue.

you could draw a punnet square, which determines the likely of which offspring carry which genes. now since white is recessive, it will be bb. and blue is dominant, either BB or Bb (carrying both dominant and recessive genes). im just going to show you a punnet square for bb and BB. with this one, 100% offspring are going to be blue. but if we were dealing with a bb and a Bb parent flower, then 25% will be white. now if this made no sense, ask your teacher, s/he will probably be able to explain it with more ease.

B B
b Bb Bb

b Bb Bb

Basic: The offspring is likely to be blue, since blue color must be dominant. Also the crossbreeding of two purebred will get a heterozygous flowering plant, and the dominant will always win over the recesive.

Advanced stuff: The offspring may be pale blue, if "incomplete dominance" occurs. But judging from your question, the basic stuff will be enough.

It's a simple logical OR function. Don't be retarded...
W || B = B
B || B = B
W || W = W

Also it can depend which has the largest stamen:
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