Carrie is testing the effects of nitrogen concentrations on the growth of algal cells. her experimental treatment consists of algal cells in beakers, each containing a different concentration of nitrogen dissolved in water. She should use a beaker containing boiled water as a negative control for the experiment. The algal cells will not grow in absence of any Nitrogen, hence the negative control will have no growing populations of algal cells. This control will add a data point for zero nitrogen concentration in the data set of varying nitrogen concentrations in the beaker.
The sun. Without the sun we would be a big ball of ice in space.
The phrase that best describe the word "energy" is letter "C. the ability to do work". The unit most commonly used to express energy is Joules (J) which is also derived from the equation of work which is the product of force and the distance that a body moves parallel to the force applied.
The statement is true that T-cells are a type of immune cell system that recognizes pathogens in the body.
T-cells are the lymphocytes that are involved in providing acquired immunity to the body. They can recognize the pathogens presented by the antigen presenting cells. There are two types of t cells: helper T cells and Cytotoxic T cells.
Immune cells are the cells of the immune system that are involved in protecting the body from infection, allergies and foreign pathogens. There are several immune cells that perform several functions. The example of such cells are: phagocytes, lymphocytes, dendritic cells, etc.
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So, there's five steps to the scientific method: Identifying the problem, forming a hypothesis, doing research and collecting background data, conducting the experiment, and finally coming to a conclusion. Arya already completed step one and two, because she sees a problem (the dry soil), and then comes up with a hypothesis, which is the water content in the soil in her yard is 2/3 lower due to the slope of her yard. Next, she's going to have to go and collect her data! This may include taking soil samples from her own yard and her other neighbors yard, and then measuring the slope of their yards ect. Then, she's going to take this information and put it into the experiment stage, and then she will come to her final conclusion!