In order to determine the effects of energy drinks on women's running speed, researchers gave 300 women an energy drink and then recorded the time it took each of them to run 2 miles. After collecting the results, researchers concluded that energy drinks increase the speed of running in women.

Which of the following further tests would best help to support this conclusion?

A. Identifying routes for future climbs is a valid reason for an expedition, but it does not directly address the historical context of the 1924 expedition.

B. Measuring oxygen levels at high elevations is a scientific endeavor that can be conducted without the specific context of replicating an earlier climb.

C. By taking the same route, in the same season, and with similar materials and equipment as the 1924 expedition, the mountaineer is likely attempting to understand the variables and challenges faced by the original team, which could provide insights into the reasons behind the failure of that expedition.

D. Demonstrating the efficacy of modern technology in making climbing safer is a plausible objective, but it does not require the replication of the conditions of the 1924 expedition. Modern expeditions typically use current technology and techniques to enhance safety, rather than deliberately using outdated methods.

A. Both endocrine and exocrine glands produce secretions that affect target cells, but the way they deliver these secretions to the target cells is different. Endocrine glands release hormones directly into the bloodstream, which then travel to the target cells, while exocrine glands secrete their products into ducts that lead directly to the target areas.

B. Nerve innervation refers to the supply of nerves to a particular part of the body or organ.

While nerve innervation can influence the activity of glands, it is not the primary distinguishing feature between endocrine and exocrine glands.

C. The biochemical nature of the secretions can vary widely among different glands, but this is not the main characteristic that differentiates endocrine from exocrine glands. Both can produce a variety of biochemical substances, including enzymes, hormones, and other compounds.

D. This is the key difference between endocrine and exocrine glands. Endocrine glands are ductless and release their hormones directly into the bloodstream, allowing them to be transported throughout the body. In contrast, exocrine glands have ducts through which they release their secretions to the surface of an organ or tissue, or to the outside of the body.

A. The browning of an apple slice is caused by the enzyme polyphenol oxidase, which is present in the apple, not the lemon juice.

B. This acidic environment can denature the polyphenol oxidase enzyme in the apple, rendering it inactive and thus preventing the browning reaction.

C. The browning is a result of a chemical reaction, and dilution would not prevent the reaction from occurring.

D. The browning is due to the formation of melanin, which are pigments resulting from the enzymatic reaction. Lemon juice's acidity affects the enzyme responsible for this reaction, not the pigments themselves.

A. A substance with a pH of 3 is not more alkaline but more acidic than a substance with a pH of 4. The pH scale measures how acidic or basic a substance is, with lower numbers being more acidic and higher numbers being more alkaline.

B. A substance with a pH of 3 is indeed 10 times more acidic than a substance with a pH of 4.

The pH scale is logarithmic, meaning each whole pH value below 7 is ten times more acidic than the next higher value.

C. A substance with a pH of 3 is not more alkaline but more acidic than a substance with a pH of 4, and the difference is not two times but ten times in terms of hydrogen ion concentration.

D. While a substance with a pH of 3 is more acidic than a substance with a pH of 4, the scale is logarithmic, so it is not simply two times more acidic, but ten times more acidic.

A. Centrosomes are the microtubule-organizing centers in cells, playing a critical role in the spatial arrangement of cell structures and in cell division.

B. Ribosomes are the molecular machines within the cell that facilitate the production of proteins by translating messenger RNA into polypeptide chains.

C. Mitochondria are known as the powerhouses of the cell, generating most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy.

D. Lysosomes are membrane-bound organelles that contain enzymes capable of breaking down all types of biological polymers—proteins, nucleic acids, carbohydrates, and lipids. They are essential for intracellular digestion, the recycling of a cell's organic materials, and programmed cell death (apoptosis).

A. Using a mortar and pestle to grind a solid reactant to a powder increases the surface area of the reactant, allowing more particles to come into contact with each other and react. This increase in surface area can significantly speed up the rate of a chemical reaction because it facilitates more frequent collisions between reactant molecules.

B. Adding more of the product would not increase the rate of the reaction; in fact, it could potentially drive the reaction in the reverse direction according to Le Chatelier's principle, which states that a system at equilibrium will adjust concentrations to counteract the effects of changes in conditions.

C. Decreasing the concentration of the reactant would generally decrease the rate of the reaction because there would be fewer reactant molecules available to collide and react with each other.

D. Sealing the reaction in an airtight container does not inherently increase the rate of the reaction. However, if the reaction produces gases, sealing it could increase the pressure inside the container, which might increase the rate of reaction depending on the nature of the reactants and products involved.

A. 5’ TCGUTCGCU 3’: This sequence is incorrect because it contains 'U', which is a base found in RNA, not DNA. DNA contains the base 'T' for thymine, not 'U' for uracil.

B. 5’ UCGAUCGCA 3’: This option is also incorrect for the same reason as option A; it includes 'U', indicating it is an RNA sequence, not a DNA sequence.

C. 3’ AGCTAGCGT 5’: This sequence is simply the original strand read in the opposite direction, not the complementary strand.

D. 3’ TCGATCGCA 5’: This is the correct complementary DNA sequence. In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Therefore, for the original DNA sequence 5' AGCTAGCGT 3', the complementary strand must read 3' TCGATCGCA 5', with each base pairing correctly according to the rules of base pairing in DNA. This sequence is antiparallel to the original, as indicated by the 3' and 5' ends, which is a key characteristic of DNA structure.

A. A tree root pushing up through the pavement is an example of a slow, powerful force that causes displacement over time, which is not similar to the sudden and explosive nature of a volcanic eruption.

B. A flood eroding the banks of a stream represents a gradual process of wearing away materials, which contrasts with the rapid release of energy and materials during a volcanic eruption.

C. A building burning to the ground is a destructive process involving combustion, which differs from the geological process of a volcanic eruption that involves the release of magma, ash, and gases from beneath the Earth's surface.

D. A can of soda fizzing when it is opened is the most similar event to a volcanic eruption.

This is because the release of carbon dioxide gas when the can is opened causes a rapid expulsion of the gas and liquid, which is akin to the sudden release of pressure and the explosive ejection of magma and gases during a volcanic eruption. This process is also known as a physical reaction, where the dissolved gases in the soda are released into the air, similar to how gases trapped in magma are released during a volcanic eruption.

A. The excretory system is responsible for the removal of waste products from the body's metabolism, including the filtration and excretion of waste material from the blood by the kidneys.

B. The digestive system breaks down proteins into amino acids through the action of enzymes. Proteins are first denatured by stomach acid, then enzymes like pepsin begin the breakdown, which is continued in the small intestine by other enzymes such as trypsin and chymotrypsin.

C. The endocrine system consists of glands that secrete hormones into the bloodstream, which regulate processes such as growth, metabolism, and sexual development. It does not play a direct role in the breakdown of proteins into amino acids.

D. The circulatory system is responsible for the transportation of blood throughout the body, which includes nutrients, gases, and waste products, but it does not break down proteins into amino acids. This process is solely the function of the digestive system.

A. Monosaccharides are the simplest form of carbohydrates and serve as the building blocks for more complex carbohydrates but are not considered macromolecules.

B. Proteins are large, complex molecules that play many critical roles in the body. They are required for the structure, function, and regulation of the body's tissues and organs. Proteins are made up of one or more long chains of amino acids, which are the building blocks of proteins. This makes them biological macromolecules.

C. Amino acids are organic compounds that combine to form proteins. They are the basic building blocks of proteins but are not macromolecules themselves.

D. Nucleic acids, such as DNA and RNA, are biopolymers essential to all known forms of life. They are macromolecules because they are composed of thousands of smaller units called nucleotides, but in this context, proteins are the more fitting example of a biological macromolecule.