1) Bones tend to become brittle with age. A disease called osteoporosis causes bones to become less dense and as a result, bones break more easily. Osteoporosis is more common among older women, because they produce less of a hormone called estrogen, which aids in bone formation. Many doctors hypothesize that older women who take estrogen supplements will experience fewer broken bones. Part A: Describe how an experiment could be designed to test this hypothesis. Part B: What would be the outcome variable (dependent variable)?

A) A Randomized Control Trial Experiment is done

B) Dependent Variable is Bone Mineral Density

Explanation:

Experimental Design:

Subjects (women) of the same age bracket (say 60-70) and having approximately the same baseline estrogen level, are recruited for the experiment, and randomly assigned into two groups of an equal number of subjects each; the test group and the control group.

The Test group is given a certain amount of estrogen supplements throughout the period of the study

The control group is given a placebo, identical to the supplements given to the test group, but without any medical significance.

Every other factor is held constant for both groups of subject throughout the period of the experiment.

After, the period of the study, the Bone Mineral Density is measured in the subjects. The Bone Mineral Density is a Radiographic Test that detects the amount of light the bone can absorb, and this is directly proportional to the health of bones. One with osteoporosis will have a less dense bone than one without Osteoporosis.

B) From the experimental design above, the independent variable is; presence or absence of estrogen supplements, while the outcome/dependent variable is Bone Mineral Density.

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?