Person #5 in the second generation marries a man who does not have cataracts. two of their four children, a boy and a girl, develop cataracts. what is the chance that their next child will be a girl with cataracts?.

1/4

Explanation:

Person 5 marries a man who does not have cataracts and produced children in which some have cataracts and others do not have. It thus means that person 5 is affected for the disorder and the man she married is a carrier (although phenotypically normal) of the disorder.

Assuming the cataract disorder allele is represented by c, unaffected version of the allele will be C. Person 5 will have the genotype cc while the man she married will have the genotype Cc.

Crossing the two:

Cc   x   cc = Cc, Cc, cc, cc

50% of the offspring are phenotypically free from cataracts while 50% have cataracts.

The probability of having a cataracts infected child is thus 50% or 1/2. This probability remains the same irrespective the number of child they have already produced.

The probability of producing a girl for every marriage is 50% or 1/2.

Hence the chance that their next child will be a girl with cataracts = probability of their next child being a girl and the probability of their next child having a cataracts.

    = 1/2 x 1/2 = 1/4

The chance that their next child will be a girl with cataracts is 1/4.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.