16. A Couple with the ability to taste PTC have two grown sons and one grown daughter. The sons have the ability to taste PTC. Their daughter is a PTC non-taster. She married with a PTC non-taster man and have two sons.
The ability to taste Phenylthiocarbamide<span> or PTC is inherited by autosomal dominant trait. The daughter of the first generation should be autosomal recessive(tt) as she was a non-taster. That means her parent would be heterozygotes(Tt) since they have the ability to taste PTC. Her brother could be homozygote dominant(TT) or heterozygote(Tt). The pedigree would be:
i. no-shade square(Tt) -----------------</span>no-shade circle(<span>Tt)
ii. </span>no-shade square(T?), no-shade square(T?), shaded circle(tt)------shaded square(tt)
iii. shaded square(tt) and shade square(tt),
17. She marries with non-taster too which means also a homozygote recessive. Since both parents are homozygote recessive, the children should be 100% homozygote recessive too.
The phenotype of the sons in generation III would be 100% non-taster.
18. The genotype of the female should be XX. To express the recessive trait, an individual need to have all recessive genes. If she has a recessive trait of an X-linked disease then both of the X genes should have a lowercase letter(recessive).
Answer:
C.


19. The genotype of a male should be XY. If he has a recessive trait of an X-linked disease then the X genes should have a lowercase letter(recessive). As there is only one X gene in male, to express recessive he only needs 1 recessive gene.
Answer:
E.

Y
I don t get it what was the question
Answer:
d. It made developing countries dependent on high-energy, imported technologies.
Explanation:
- One of the moan problem associated with the green revolution was that the developing countries were highly dependent on the use of the HYV seeds.
- And this allowed for them to have assess to high technology and this increased the rate of the energy demands and the importing of the high efficient technology.
The Ghana empire ruled before great empires of Mali and Songhai,
Explanation:
The two empires of the region , along with Ghana were the last great owners of the Saharan Africa before colonialism and had been there for a long time thus.
They were profiting from the trade routes set up in the time of the rule of Mansa Musa
This is the time of the precedence of the Ghana empire in the whole region which then broke up into small pieces and then the great empires of Mali and Songhai sprung up after it.