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Carbon dating of charcoal gathered from a Nok iron smelter at Intini. Nigeria, suggests thai iron technology was established there by 410 B.C. This may not be the oldest smelter in sub-Saharan Africa, however.
Archaeologists have located evidence of iron-smelting in the Termit Hills of Niger from as early as 1400 B.C..
but skeptics say the wood used for that dating could have already been centuries old when burned as fuel-a problem that dogs carbon dating, especially in arid places like Niger, where wood desiccates and lasts longer.
Of course, the same problem could distort dates for the Intini furnace as well, but here there is an important piece of corroborating evidence: Nok pottery found inside the furnace alongside the charcoal The passage is primarily concerned with

• A. contrasting the iron-smelting techniques of two civilizations in sub-Saharan Africa
• B. assessing certain advantages and disadvantages of carbon dating in sub-Saharan Africa
• C. dating the development of iron technology in sub-Saharan Africa
• D. suggesting a possible link between climate and technological development in sub-Saharan Africa
• E. determining which of two ancient cultures in sub-Saharan Africa was more technologically advanced

In the figure above, what is the length of AB?

• A. 16
• B. 15
• C. 17
• D. 19
• E. 18

Pumping at a constant rate, a certain gasoline pump can fill an empty 50-gallon tank in 2 minutes. If the pump pumped gasoline into the 50-gallon tank at the constant rate for 1.5 minutes and the tank had 10 gallons of gasoline in it when the pump began pumping, what percent of the volume of the 50-gallon tank was filled with gasoline at the end of the 1.5 minutes?

Sets A and B contain 40 and 30 elements, respectively, and 16 of the elements in B are not in A.
Set C is the set of all elements that are in .-1 or in B or in both. One element is to be selected at random from C.
What is the probability that the selected element will be a member of both A and B ?
A)

B)

C)

D)

E)

• A. Option C
• B. Option B
• C. Option D
• D. Option A

In the brushland of Klanos Island, seeds of the plant Emmenan the penduliflora normally stay dormant for years and germinate only after a brushfire. The resulting plants quickly mature, produce seed, and then die. It is the nitrogen dioxide in (he smoke that induces the seeds lo germinate. Because automobiles are being introduced on Klanos. and their exhaust contains nitrogen dioxide, the plants will probably be seen throughout Klanos every year.
Which of the following, if true, most seriously weakens the argument?

• A. The seeds of some of the other plants that are found on Klanos do not germinate unless the seed coat that protects the kernel of the seed is cracked by intense heat.
• B. Fires in the habitat off. penduliflora entirely destroy the plant's seeds in the places where the fires bum most intensely.
• C. Fires clear much of the brush in the habitat off. penduliflora. allowing germinating seeds to receive enough sunlight to grow.
• D. All efforts to reduce the frequency and intensity of brushfires on Klanos have failed.
• E. A small amount of nitrogen dioxide, such as is contained in the exhaust of two or three automobiles, is sufficient to induce the germination of nearby seeds off. penduliflora.