Help PLZ!!!?

1 - A couple has two children, both of whom are boys. What is the chance that the parents next child will be a boy


a. 0%


b. 25%


c. 50%


d. 75%





2 - A female guinea pig homozygous dominant for black fur color is mated with a male homozygous for white fur.?


In a litter of eight offspring, there would probably ?





a. 8 black guinea pigs.


b. 4 black and 4 white guinea pigs


c. 2 black, 4 gray, and 2 white guinea pigs


d. 8 gray guinea pigs





3 - Eye color in humans is the result of_________inheritance.


a - multiple allelic


b - polygenic


c - sex-linked


d - simple dominant





PLZ PLZ help me OUT!! Thank you so MUCH!!!

Help PLZ!!!?
You really need to look this up on your own - however - I will help you.





1. Is c. 50%, (50% boy, 50% girl) -- past children do not affect the probability of the gender of future children.





2. I would go with A, if the white guinea pig is supposed to be recessive - each baby gets one copy of each gene (AA black, and bb, white) and they all end up (Ab) - with A (black) dominating over b (white).





3. Is, I beleive, B. as polygenic means with multiple genes, and eye color is controlled with at least 3 separate genes.
Reply:8 black guinea pigs. if the black is dominant, then when u cross a homozygeous(2 black chromsones, not a white carrier), witha white ressesive guiena pig, you will end up with 8 black guinea pigs whoa re carrieres of the white reccesive gene.
Reply:1-c just for ur information whenever u r asked about a probaility of a boy or a girl it is 50% it never changes as u may get an x from female or a y from male so it is the same chance





2-b this is because dominant overweighs the recissive genes , so by cross u get all ve a dominant gene, they dont have to be homozygous, just heterozygous is enough to express the black gene





3-a its an easy question, colour of eyes is determined by many genes, many of them. one can ve a black eye, other brown , other blue, other yellow...etc.


the dominant colour is expressed, so if a boy has a black allele and a blue one, it is known that black is dominant, so the boy gets black eyes.


it is multiple allelic as eye colour can be coded by many types of alleles, not just 2 as in tallness either tall or short.
Reply:1.C


the chance getting a child is 50-50.its not depending on the gender of d first children.





2.A


if female is homozygous dominant 4 black fur(ie.BB) is mated with male homozygous 4 white fur(ie. bb)


the offspring will be ( Bb )that is black fur.


this is bcoz black fur is dominant.





3.C(its my answer,x sure)


eye colour in humans is result of sex-linked that means depend on d colour of the eyes of both parent.
Reply:Answer Certainty


C 100%


A 100%


B 75% (might be A)