Question

the sahara desert and the nile river are the two components of egypts natural environment. nile water is the main water source for civilization in egypt. only 5% of the total area, residing along the banks of the nile, is arable land for crop production. annual flooding of the nile supplies water for crop production. without this water source, civilization in egypt would be very different. records indicate that a drought caused the demise of egypts old kingdom (2886 - 2181 bce). because of an insufficient water supply and food production decreased, the population suffered from famine. scientists have recently investigated whether other evidence supports the theory that a shift in the political system destabilized egypt. they have found evidence of political upheaval in egypt about 4,200 years ago. one group of researchers removed a sediment core from the nile delta. the environmental conditions over thousands of years allowed researchers to investigate hypothesized conditions over those periods. the researchers hypothesized and observed that periods of low concentrations of pollen from wetland plants and elevated concentrations of microscopic charcoal would occur together during a decrease in vegetation and an increase in natural fires during drought years. a second group of researchers also examined sediment deposits by analyzing the amounts of sediment deposited over time. these researchers hypothesized that a decrease in rainfall would lead to decreased vegetation cover, which in turn would lead to increased runoff and increased sediment deposition in the delta. this increase in runoff would lead to increased erosion, which could be observed as erosional events in cores and could be observed as erosional events in cores and could be observed as larger deposits of sediment within the cores. what else should the second group of researchers measure to test its hypothesis? a. the current levels of water in the river b. the type of pollen in cores from a nondrought period c. the composition of microscopic charcoal released during natural fires d. the quantities of sediments in cores from the delta during a nondrought period

Explanation:

The second - group of researchers hypothesized that a decrease in rainfall over time led to sediment deposition changes. To test this, they would need to measure something related to rainfall or its effects. Measuring the current levels of water in the river (Option A) could potentially give an indication of past rainfall patterns as water levels are related to rainfall input. Other options like pollen in cores (Option B) are more related to vegetation and climate in general rather than specifically rainfall - related sediment deposition. Microscopic charcoal (Option C) is related to natural fires and not directly to rainfall - sediment connection. Quantities of sediments in cores during non - drought periods (Option D) do not directly test the rainfall hypothesis as they do not focus on the rainfall variable itself.

Answer:

A. the current levels of water in the river