A scientist is comparing the outer layer of an onion cell to the outer layer of a human skin cell. What is unique about the outer layer of the onion cell compared to the skin cell?
It contains proteins.
It contains cellulose.
It contains carbohydrates.
It is selectively permeable.
The unique characteristic of the outer layer of the onion cell compared to the skin cell is that it contains cellulose. Cellulose is a structural carbohydrate found in the cell walls of plant cells, including onion cells. In contrast, the outer layer of a human skin cell does not contain cellulose. Other options mentioned, such as proteins, carbohydrates, and selectively permeable nature, can be found in both onion cell and skin cell membranes.
Stella wants to test the hypothesis “If carbon dioxide levels increase, the growth rate of sunflowers will increase.” She places five young sunflower plants into similar containers and sets up pumps that release different amounts of carbon dioxide into each container. She plans to measure the daily height of the plants for two weeks and graph the data.
Which option would allow Stella to set up a control group for the experiment?
She should provide mist to each of the plants except one plant to keep the air moist and fertilize the plants.
She should give the plants receiving the least CO2 a little more oxygen to compensate for the difference in gases.
She should give all the flowers the same amount of water.
She should place one flower in a similar container, but not pump carbon dioxide into it.
The option that would allow Stella to set up a control group for the experiment is:
"She should place one flower in a similar container, but not pump carbon dioxide into it."
A control group is a group or individual that does not receive the treatment being tested. In this case, it means having a sunflower plant in a similar container without any changes to its carbon dioxide levels. This will allow Stella to compare the growth rate of the sunflower plants that were exposed to different levels of carbon dioxide with the growth rate of the sunflower plant in the control group, providing a baseline for comparison.