Answer:
1. Obtain two identical containers and dry sand.
2. Shape equal amounts of sand into a "slope on the side of" each container.
3. Spray water on the sand in one container. The sprayed water represents "rainfall"
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4. In the other container, "place ice cubes to melt on the sand. This represents snow or glaciers."
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5. Observe and record the changes in the sand.
6. Analyze differences between the two containers.
Explanation:
Mine hasn't been graded yet but I'm pretty sure this is the right answer. I'll come back once it's graded and say.
Prenatal care as well as preconception can help prevent complications and inform women about important steps they can take to protect their infant and ensure a healthy pregnancy.
Answer:
Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.
Explanation:
Helper T cells become activated when they are presented with peptide antigens by MHC class II molecules, which are expressed on the surface of antigen-presenting cells (APCs). Once activated, they divide rapidly and secrete cytokines that regulate or assist the immune response.
