This is a “true” story). At a college fair, the biology department was using PTC paper to demonstrate dominant and recessive phenotypes. People who have a copy of the dominant allele (T) can taste the PTC. Non-tasters have two copies of the recessive allele (t). A married couple with a baby came up to the demonstration. The husband and wife determined they were both non-tasters. The husband put a strip of PTC paper into the baby's mouth and the baby made a face and spit it out. To see if it was just paper the baby didn't like, the husband gave the baby a regular piece of paper with no PTC on it. The baby happily sucked on the plain paper. The husband gave the baby another piece of PTC paper, and the baby spit it out immediately and began to cry. A while later the couple was seen with the wife crying and the husband yelling

answer: a) a compound microscope has a greater magnification ability than a simple microscope.

explanation:

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.