imone/ARB huggingface dataset:
Question: The kidneys are responsible for filtering certain components of blood and producing urine from them. In an adult, the kidneys are typically capable of processing about 1 to $1.5$ liters of water per hour depending on the individual and conditions within the body. In a condition known as water intoxication, a person ingests more water (usually 3 or more liters in a single sitting) in a shorter period of time than the kidneys can process. In a child, the amount of water required to induce water intoxication is much less.  The regulation of water and sodium levels in the nephrons is adjusted in two regions of the kidneys where water and sodium can be reabsorbed from the nephron and returned to circulation. Those regions are the:

Options:
A. proximal convoluted tubule and distal convoluted tubule
B. the loop of Henle and the distal convoluted tubule
C. the distal convoluted tubule and the collecting duct
D. the proximal convoluted tubule and the loop of Henle
Answer: In the proximal convoluted tubule, the primary events are the reabsorption of nutrients and water. There are two regions in the nephron where large amounts of sodium and water are reabsorbed. In the loop of Henle, the countercurrent multiplier system is used, which leads to the reabsorption of salts (sodium and chloride) and water. In the distal convoluted tubule, the hormone aldosterone influences the reabsorption of salts and water followed by osmosis. The correct answer is B.
Question: \section{
In October 2012, Felix Baumgartner attempted a world-record sky-diving jump from just over 128,000 ft (39,014 m) above the Earth's surface. He was fitted with a customized, pressurized spacesuit that brought his total weight to $260 \mathrm{lbs}$ ( $1156 \mathrm{~N}$ ). The spacesuit was designed to collect and transmit important monitoring, communications, and tracking information throughout the jump. Baumgartner then ascended to the jumping altitude housed within a pressurized capsule of weight 2900 lbs ( $12900 \mathrm{~N})$ attached to a $30 \times 10^{6}$ cubic feet $\left(8.5 \times 10^{8} \mathrm{~L}\right)$ helium-filled weather balloon. The weather balloon with the attached capsule ascended at a rate of $1000 \mathrm{ft} / \mathrm{min}(5.1 \mathrm{~m} / \mathrm{s})$, reaching the jumping altitude in approximately two hours.
Once the capsule reached the jumping altitude, the door to the capsule was opened and Baumgartner stepped out and fell forward, beginning his free-fall descent. He continued falling until he reached a maximum speed of $834 \mathrm{mph}(373 \mathrm{~m} / \mathrm{s})$, which exceeded the speed of sound. This speed was Baumgartner's terminal velocity-the velocity attained in which he was no longer being accelerated downward due to gravity. Once he reached this speed, Baumgartner deployed his parachute and glided safely to Earth's surface.Assuming the density of helium is $0.1785 \mathrm{~g} / \mathrm{cm}^{3}$, the weight of the helium used to inflate the balloon was:

Options:
A. $1.5 \times 10^{8} \mathrm{~N}$
B. $1.5 \times 10^{7} \mathrm{~N}$
C. $1.5 \times 10^{6} \mathrm{~N}$
D. $1.5 \times 10^{5} \mathrm{~N}$
Answer: Using the relationship The correct answer is C.
Question: Questions 18-20 are based on the following data.
The generalized events in DNA replication can be depicted by the following flowchart:
Double helix $\rightarrow$ Nicking of a strand $\rightarrow$ Unwinding $\rightarrow$ Destabilization and relief of pressure $\rightarrow$ Initiation $\rightarrow$ Elongation $\rightarrow$ Closing of nicks
Between which two steps would the enzyme topoisomerase be used?

Options:
A. Double helix $\rightarrow$ Nicking of a strand
B. Nicking of a strand $\rightarrow$ Unwinding
C. Initiation $\rightarrow$ Elongation
D. Elongation $\rightarrow$ Closing of nicks
Answer: Topoisomerases are enzymes that cut one of the DNA strands so that it can begin to unwind and serve to relieve pressure in the coil caused by its unwinding. Thus the enzyme acting between Double helix $\rightarrow$ Nicking of a strand is topoisomerase. The correct answer is A.
Question: \section{Passage $\mathrm{V}$}
A student performed qualitative tests on a series of unknown chemicals in order to identify them. The unknowns included $\mathrm{NaCl}, \mathrm{NaHCO}_{3}$, sugar $\left(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\right), \mathrm{MgSO}_{4}$, $\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}$, cornstarch, and chalk $\left(\mathrm{CaCO}_{3}\right)$. These are all household chemicals. $\mathrm{MgSO}_{4}$ is Epsom salts, $\mathrm{NaHCO}_{3}$ is baking soda, and $\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}$ is photographic fixer. The student was asked to identify six unknowns: A, B, C, D, E, and F.
The qualitative tests were based on the following:
$>$ Solubility in water: starch is insoluble, as well as one of the other compounds. The rest are soluble in water.
$>$ Chalk produces a gas when treated with acid.
$>$ Starch turns blue when treated with iodine.
$>\mathrm{MgSO}_{4}$ produces a milky precipitate when treated with aqueous ammonia.
$>\mathrm{NaHCO}_{3}$ turns pink when treated with phenolphthalein.
$>\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}$ decolorizes iodine solution.
$>\mathrm{NaCl}$ conducts electricity in solution.
$>$ Sugar does not conduct electricity in solution.
The student prepared a flowchart that would aid in doing the experiments in a systematic manner and allow efficient identification of the unknowns.
\section{Experiment}
The experiments were conducted in the following order. The solubility of each chemical in water was tested first. From those results, the insoluble unknowns were tested next. The unknowns that were soluble in water were tested as aqueous solutions, rather than tested for conductivity.
\section{Results}
\begin{tabular}{ccccccl}
\hline Unknown & Solub & Conductivity & Acid & Phenolphthalein & $\mathbf{N H}_{\mathbf{3}}$ & $\mathbf{I}_{\mathbf{2}}$ \\
\hline A & $\mathrm{Y}$ & $\mathrm{Y}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{N}$ \\
B & $\mathrm{N}$ & $\mathrm{Y}$ & $\mathrm{Y}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{N}$ \\
C & $\mathrm{Y}$ & $\mathrm{Y}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{Y}$ & $\mathrm{N}$ \\
$\mathrm{D}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{Y}_{\mathrm{BLUE}}$ \\
E & $\mathrm{Y}$ & $\mathrm{Y}$ & $\mathrm{Y}$ & $\mathrm{Y}$ & $\mathrm{N}$ & $\mathrm{N}$ \\
F & $\mathrm{Y}$ & $\mathrm{Y}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{N}$ & $\mathrm{Y}_{\text {COLORLESS }}$ \\
\hline
\end{tabular}
From these results the student was able to identify all six unknowns.
Unknown A was determined to be:

Options:
A. $\mathrm{CaCO}_{3}$
B. $\mathrm{NaCl}$
C. $\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}$
D. starch
Answer: Unknown A is soluble in water and has negative results for all of the tests except for conductivity, so it must be $\mathrm{NaCl}$. The correct answer is B.
Question: Endothelin is a vasoactive peptide involved in a variety of processes, including the control of blood flow. Endothelin is capable of binding to two different receptors. There are receptors for endothelin located on smooth muscle (ETA) and receptors for endothelin located on vascular endothelium (ETB). When endothelin binds to ETA, it initiates vasoconstriction by narrowing blood vessels. However, when endothelin binds to ETB, vasodilation occurs due to the widening of blood vessels. The activity of the ETB receptor seems to counterregulate the ETA effects and prevents excessive vasoconstriction.
Drug $X$ is a selective receptor antagonist for endothelin. It is designed to bind preferentially to certain endothelin receptors. Drug $\mathrm{Y}$ is another selective receptor antagonist for endothelin. It is also designed to preferentially bind to one of the endothelin receptors. Researchers are hopeful that drugs $\mathrm{X}$ and $\mathrm{Y}$ will be of value in the treatment of conditions such as pulmonary arterial hypertension (PAH). In PAH, excess endothelin is produced, which causes an increase in blood pressure within the pulmonary arteries. Normal pressure in the pulmonary arteries is expected to be about $14 \mathrm{~mm} \mathrm{Hg}$, and pressure at or above $25 \mathrm{~mm}$ Hg constitutes PAH. Both drugs have been tested in patients with PAH. There were five patients in each group. At the end of the study, the percent decrease in mean pulmonary artery pressure was measured for each patient and reported in the table.
\begin{tabular}{cccc}
\hline Patient & Drug X & DrugY & Placebo \\
\hline 1 & $+10 \%$ & $-10 \%$ & $+5 \%$ \\
2 & $+3 \%$ & $-5 \%$ & $0 \%$ \\
3 & $-5 \%$ & $+2 \%$ & $+13 \%$ \\
4 & $+2 \%$ & $0 \%$ & $-4 \%$ \\
5 & $0 \%$ & $-7 \%$ & $-2 \%$ \\
Average decrease & $+2 \%$ & $-4 \%$ & $+2.4 \%$ \\
\hline
\end{tabular}
In addition to regulation of vessel diameter, ETA is known to have other roles in the body. When activated by a specific type of endothelin, ETA can synergize with growth factors to cause rapid cell proliferation. Based on this information, it is MOST likely that ETA can be involved with:

Options:
A. an increase in metabolism
B. the development of cancer
C. immune system hypersensitivities
D. increased stress to the kidneys and liver
Answer: The question suggests that ETA can be activated by certain types of endothelin, which causes ETA to synergize with growth factors to increase cell proliferation rates. Growth factors are one of many mechanisms used to regulate the cell cycle. Of the choices listed, A, C, and D can be eliminated as they have nothing to do with growth factors and cell proliferation. The only reasonable answer is choice B since one of the many characteristics of cancer is increased cell proliferation. The correct answer is B.