Question

questions 4 and 5 refer to the following passage.
nearly 75% of plant and animal species on earth, including all non - bird dinosaurs, went extinct during the cretaceous - paleogene (or cretaceous - tertiary) extinction event. scientists have spent years speculating about what precipitated this extinction event. various hypotheses have been presented to account for the disappearance of these huge creatures. the prevailing theory is that a large asteroid collided with earth and its impact raised a cloud of dust that reduced the amount of sunlight that reached the planet’s surface for many years.
temperatures fell rapidly, and without the normal amount of sunlight, much of the plant life on the planet’s surface disappeared. unadapted for sudden lower temperatures and a much smaller food supply, the dinosaurs, as well as many other species, became extinct.
in support of this theory, scientists have found a thin layer of sediment in marine and terrestrial rocks that contains metals that are rare on earth but abundant in asteroids. additionally, a large crater was found in the gulf of mexico that must have been formed when an asteroid hit earth at roughly the same time as the extinctions took place.
amid the destruction was an opportunity for evolution. there were countless vacated ecological niches and the surviving organisms rapidly adapted and developed in order to occupy these niches. it is believed that several of the mammals, including the ancestors of primates, that are alive today developed during this time.

1. if the preceding information is true, which of the following is the most likely explanation for the fact that there is still life on earth today?

a. some forms of life were able to survive in spite of the decrease in available sunlight.
b. the dinosaurs went into hibernation.
c. sunlight is unnecessary for the survival of plant forms.
d. there was no food at all on the planet’s surface during these years.

1. if charles darwin read this passage, would he agree with the statements made in the last paragraph?

a. no. according to darwin’s theory of natural selection, organisms were destined to fulfill specific niches only when it was best for their evolutionary fitness.
b. no. darwin would not have considered a tragedy to be an opportunity.
c. yes. darwin believed that slight differences between organisms can be selected for through natural selection and that this would be exacerbated in a time when there were many potential ecological niches.
d. yes. darwin believed that individual organisms were capable of evolution.
question 6 is based on the following information.
the circulatory system, sometimes called the cardiovascular system, consists of the heart and the blood vessels. its main function is to move the blood, which transports substances like oxygen and nutrients, throughout the body. the major organ of the circulatory system is the heart, a muscle that contracts to pump blood. blood moves through the blood vessels from large arteries, to smaller arteries, to capillaries, to small veins, to large veins, and back to the heart. through the thin walls of the capillaries, oxygen, nutrients, and other substances pass from the blood into the body’s cells, and carbon dioxide and other wastes pass from the cells into the blood.

1. in the 17th century, english physician william harvey concluded that blood in the veins flows toward the heart. which of the following facts helps support harvey’s conclusion?

a. the heart pumps about 1,800 gallons of blood per day.
b. the heart has four chambers: two atria and two ventricles.
c. large veins branch into smaller blood vessels called capillaries.
d. veins have valves that allow blood to flow in one direction only.
question 7 is based on the following passage
homeostasis refers to an organism’s ability to maintain a nearly constant internal environment within a narrow range that supports life. examples of homeostasis in humans and other mammals include regulation of: body temperature, blood ph, and concentration of glucose in the blood. these homeostatic mechanisms actively maintain a stable internal environment, even when changes occur in the organism’s external environment.
one example of homeostasis in humans involves regulation of the blood glucose concentration, also known as blood sugar. after a meal, glucose levels in the blood may rise above the normal set point of about 90 milligrams per 100 milliliters of blood plasma. beta cells in the pancreas detect the rise in blood glucose and respond by secreting insulin into the bloodstream. the insulin acts as a signal to certain cells to increase uptake of glucose. the increased uptake of glucose from the blood lowers the blood glucose level back to the normal set point. the glucose that has been taken up by cells will be used for energy or converted to glycogen, a storage polysaccharide.
if the level of blood glucose drops too low, such as between meals, pancreatic alpha cells are stimulated to secrete glucagon into the blood. glucagon is a hormone that signals cells in the liver to convert glycogen to glucose. glucose is then released back into the bloodstream to return the blood glucose level to the normal set point.

1. which of the following conclusions is supported by the passage?

a. a person whose alpha cells do not function would be unable to produce glycogen.
b. a person whose alpha cells do not function would be unable to produce insulin.
c. a person whose beta cells do not function would be expected to have a higher - than - normal blood glucose level.
d. a person whose beta cells do not function would be expected to have a higher - than - normal glycogen level.
refer to the following passage to answer question 8.
jill wants to determine the likelihood of the stem length of the offspring of the two plants she plans to crop. she knows that each plant has two alleles for stem length. the alleles are characterized by letters in the form of genotype. one plant has a genotype of ll with long stem length. the other plant also has a genotype of ll

Explanation:

Question 4

To solve this, we analyze each option:

• Option A: The passage says sunlight decreased, but some life survived. This aligns with the idea that some forms adapted to less sunlight.
• Option B: The passage doesn't mention dinosaurs hibernating.
• Option C: The passage states plant life disappeared without normal sunlight, so sunlight is necessary for plants. Eliminate C.
• Option D: The passage says "much" plant life disappeared, not all food. Eliminate D.

So A is the best explanation.

Darwin's theory of natural selection involves organisms with beneficial traits surviving and reproducing, and niches being filled by adapted organisms.

• Option A: Darwin's theory doesn't say organisms are "destined" for niches. Eliminate A.
• Option B: The last paragraph says extinction was an opportunity for evolution, Darwin would see it as such, not a tragedy. Eliminate B.
• Option C: Darwin believed natural selection acts on differences, and with many niches, this would be enhanced. This matches the last paragraph's idea of organisms adapting to niches.
• Option D: Darwin's theory is about populations evolving, not individual organisms. Eliminate D.

So C is correct.

Harvey's conclusion is that veins carry blood toward the heart. We need a fact supporting one - way flow to the heart.

• Option A: Heart's daily blood pumping doesn't relate to vein flow direction. Eliminate A.
• Option B: Heart chambers don't relate to vein flow toward heart. Eliminate B.
• Option C: Veins branching into capillaries doesn't show flow toward heart. Eliminate C.
• Option D: Vein valves allowing one - way flow (toward heart) supports Harvey's conclusion.

Answer:

A. Some forms of life were able to survive in spite of the decrease in available sunlight.

Question 5