Stella starts the activity by collecting water from a pond near her school and making a wet mount slide. She places a drop of pond water onto a glass slide and covers the water droplet with a small, glass cover slip. Stella then carefully lowers the stage on the microscope and secures her wet mount slide to the stage using the microscope’s stage clips. Next, Stella turns the base light of the microscope on so that a light is shining from below the stage and spotlighting the specimen on the pond water slide. Stella then rotates the objective lenses on the microscope so that the smallest magnification objective (4X) is aligned with the eyepiece and the slide. Because the eyepiece of her compound microscope has a constant magnification of 10X, Stella’s compound microscope is now set to a 40X magnification power. In addition to the 4X objective lens, Stella’s microscope has 10X and 40X objective lenses. Question Question 1 Based on this information, what is the highest magnification power that Stella's microscope can achieve? 400X 100X 1000X 40X

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint

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.

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explanation:

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