6. Alex wanted to find out what toothpaste made teeth the cleanest. Everyday she brushed her teeth with a different product and then took a plaque test to see how much plaque was left. She used Crest, Colgate, Close-up, and water. a. Independent Variable (IV): b. Dependent Variable (DV): c. Control: d. Constants:

Independent variable: Different products of toothpaste

Dependent variable: Amount of plaque left in her teeth

Control group: Water

Constant: Same amount of time for product to have an effect

Explanation:

Independent variable is the variable that is subject to manipulation or change by the experimenter in order to effect a measurable response. The independent variable in this experiment is the DIFFERENT PRODUCTS OF TOOTHPASTE USED.

The dependent variable is the variable that is measured during the experiment. In this experiment, the dependent variable is the AMOUNT OF PLAQUE LEFT IN ALEX'S TEETH.

The control group in an experiment is the group that does not receive the treatment/independent variable. In this case, the usage of WATER is the control.

The constant is the variable kept the same for all the groups in the experiment. In the case, the Same amount of time for each product to have an effect on her teeth is the CONSTANT.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."

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.