[Q]: Mary and Ann are mother and daughter. Mary is in her 70's while Ann is in her late 40's. They both work out regularly for improved health. Mary has been experiencing some health issues lately. Which person experienced a decrease in strength? Hint: During late adulthood, the risk of developing diseases such as cardiovascular diseases and cancer continues to rise. Most people also have a decline in strength and stamina. Their senses may start failing, and their reflex time typically increases. Their immune system also doesn't work as well as it used to. As a result, common diseases like the flu may become more serious and even lead to death. The majority of late adults develop arthritis, and as many as one in four develop Alzheimer's disease.
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[A]: Mary

[Q]: Hannah and Joe are two colleagues. They both study horticulture. They've been studying ants lately for their entomology class. Hannah studied ants that farm aphids, while Joe studied ants that farm fungus. Which student learned more about ants fighting off aphid predators? Hint: Some species of ants farm aphids, protecting them on the plants where they are feeding, and consuming the honeydew the aphids release from the terminations of their alimentary canals. This is a mutualistic relationship, with these dairying ants milking the aphids by stroking them with their antennae. Although mutualistic, the feeding behaviour of aphids is altered by ant attendance. Aphids attended by ants tend to increase the production of honeydew in smaller drops with a greater concentration of amino acids.Some farming ant species gather and store the aphid eggs in their nests over the winter. In the spring, the ants carry the newly hatched aphids back to the plants. Some species of dairying ants (such as the European yellow meadow ant, Lasius flavus) manage large herds of aphids that feed on roots of plants in the ant colony. Queens leaving to start a new colony take an aphid egg to found a new herd of underground aphids in the new colony. These farming ants protect the aphids by fighting off aphid predators.
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[A]: Hannah

[Q]: David needs to purchase a camera for his photography class. He went to the local consumer electronics store to find himself a good camera. Two cameras caught his eye, camera A and camera B. Camera A had a very small pinhole, but camera B had larger aperture. David needs to decide which camera should he buy. Which camera would have lower f-number focusing lens, camera A or camera B? Hint: In practice, the diameter of the aperture is chosen based on the focal length of the lens, the diameter and quality of the input beam, and its wavelength (longer wavelengths require larger apertures). If the hole is too small, the beam quality is greatly improved but the power is greatly reduced. If the hole is too large, the beam quality may not be improved as much as desired. The size of aperture that can be used also depends on the size and quality of the optics. To use a very small pinhole, one must use a focusing lens with a low f-number, and ideally the lens should not add significant aberrations to the beam. The design of such a lens becomes increasingly more difficult as the f-number decreases.
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[A]: camera A

[Q]: Last week, John visited the national park near his city. He saw many flowers. His guide explained him that there are two categories of flowers, category A and category B. Category A flowers spread pollen via wind, and category B flowers spread pollen via animals. Would category A flower have higher or lower efficiency of fertilization than category B flower? Hint: Scientists think that the earliest flowers attracted insects and other animals, which spread pollen from flower to flower. This greatly increased the efficiency of fertilization over wind-spread pollen, which might or might not actually land on another flower. To take better advantage of this "animal labor," plants evolved traits such as brightly colored petals to attract pollinators. In exchange for pollination, flowers gave the pollinators nectar.
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[A]:
lower