Question

Lydia hypothesizes that warmer temperatures promote faster cell division. Which experimental design would best allow Lydia to test her hypothesis?
A.
Fill three identical flasks full of nutrient broth with 10, 20, or 30 bacterial cells. Then, place all three flasks into an incubator at 25°C. Finally, measure how many bacterial colonies are in each flask after four hours have passed.
B.
Place twenty bacterial cells in each of three identical flasks full of nutrient broth. Then, place each flask in an incubator set at 10°C, 20°C, or 30°C. Finally, measure the number of bacterial cells in each flask every twenty minutes for four hours.
C.
Use a toothpick to scrape cheek cells from the inside of the mouth. Place the cheek cells in the center of a petri dish. Light a match and place the match in the petri dish with the cells. Cover the petri dish until the match burns out. Then, measure the number of cells in the dish.
D.
Use a toothpick to scrape cheek cells from the inside of the mouth. Place the cheek cells in formaldehyde to preserve them and then stain them with purple dye. Create a wet mount of the cheek cells and observe them under a microscope.

Answer 1

Answer: Option B

Explanation:

The hypothesis states that the cell division is dependent on the temperature. It states that high temperature favors more cell division.

Here, in the experiment the independent variable is temperature because we can control the temperature.

The division of cell is dependent variable because it is dependent on the temperature range.

In the given statement the bacterial colonies are grown on three different temperatures so that the cell count can be observed. This is the best option suiting the hypothesis.

Answer 2

B because youre testing it at different temperatures