Based on the diagram, the 1mm (which is equivalent to 1000µm) field of view contains approximately 5 cells. Thus, to get the average size of each cell in µm, we divide 1000µm with 5, and this is equal to 200µm.

Incorrect answers:

(1) 10 µm

If the size of each cell is only 10µm, then there must be 100 cells (1000µm divided by 10µm) in the field of view of the microscope instead of only 5 cells.

(2) 100 µm

If the size of each cell is only 100µm, then there must be 10 cells (1000µm divided by 100µm) in the field of view of the microscope instead of only 5 cells.

(4) 2000 µm

For experiments like this, it is important to have a control setup, wherein a variable must remain unchanged or held constant to prevent its effects on the outcome and thus verifies the behavior of and the relationship between independent and dependent variables. In this particular experiment, it could have been easier to measure the efficacy of the mineral supplement if a control setup was present by simply comparing the health conditions of the control and those that took up mineral supplements in two different dosages.

Incorrect answers:

(1) test only one group with 200mg of the supplement

Control setups are important to test the validity of the results. Thus, only one setup will leave the researchers with no point of comparison with other factors that could have affected the results of the experiment.

(2) test the supplement on both groups for 5 weeks instead of 10 weeks

Decreasing the time period of the experiment to 5 weeks could lead to invalid results because the time frame is too short.

(3) test a third group that receives 150mg of the supplement

The controlled variable in this study is the nonsmoker wife that carries the baby. In the two setups, both mothers do not smoke. As seen in the results, babies with fathers that smoke have significantly lower body weights compared with those that were not exposed to smoking. Thus, secondhand smoking could be a major factor in the low body weight of the babies.

Incorrect answers:

(1) is unable to pass from the mother to the fetus

It is very likely that the mother can pass the smoke she inhaled from the outside environment to the fetus because the fetus' intake of oxygen depends solely on the mother.

(3) causes mutation in cells of the ovaries

Smoke cannot cause mutation of cells in the ovaries because the cells are not directly exposed to smoke. Mutation is often caused by direct exposure to radiation or toxic chemicals.

(4) blocks the receptors on antibody cells

Smoke cannot block receptors on antibody because they are not directly exposed to smoke.

Correct answer:

Correct answer: