Parasitic worm infestation is hypothesized to be damaging to the host.

However, scientists have recently discovered that worm infestation can relieve the effects of certain autoimmune disorders.

In which of the following ways should the hypothesis be modified, given the new findings?

 

The polarity of water molecules explains its solvent abilities for certain substances.

Water is a polar molecule because it has a partial positive charge on one end and a partial negative charge on the other end due to the unequal sharing of electrons between the oxygen and hydrogen atoms.

This polarity allows water to dissolve other polar substances and ionic compounds.

Choice A.

Kinetic energy of liquid water molecules is not the correct answer because kinetic energy refers to the energy of motion and does not directly explain water’s solvent abilities.

Choice B.

High specific heat is not the correct answer because specific heat refers to the amount of heat required to raise the temperature of a substance and does not directly explain water’s solvent abilities.

Choice C.

High surface tension is not the correct answer because surface tension refers to the cohesive forces between liquid molecules and does not directly explain water’s solvent abilities.

Diffusion down a concentration gradient causes most of the carbon dioxide from the blood to move into the alveoli.

The alveoli are tiny air sacs in the lungs where gas exchange occurs.

Carbon dioxide is a waste product of cellular respiration and is carried by the blood to the lungs to be exhaled.

In the lungs, carbon dioxide diffuses from the blood (where its concentration is high) into the alveoli (where its concentration is lower) down its concentration gradient.

Choice A is incorrect because carbon dioxide is not converted to carbon monoxide in the body.

Choice C is incorrect because passive transport using carrier proteins is not the primary mechanism by which carbon dioxide moves from the blood into the alveoli.

Choice D is incorrect because active transport using energy is not involved in the movement of carbon dioxide from the blood into the alveoli.

The atomic number of an element represents the number of protons in the nucleus of an atom of that element.

Since lithium has an atomic number of 3, it has 3 protons in its nucleus.

Choice A is not correct because 7 is the mass number of lithium, not the number of protons.

Choice C is not correct because 12 is not the atomic number or mass number of lithium.

Choice D is not correct because 4 is not the atomic number or mass number of lithium.

The hypothesis should be modified to include the new findings that worm infestation can relieve the effects of certain autoimmune disorders.

A possible modification could be: “Parasitic worm infestation can have both damaging and beneficial effects on the host.

While it can cause harm, it has also been found to reduce the severity of certain autoimmune disorders.”

Choice A.

Worm infestation prevents the body from immune malfunction is not correct because it overstates the findings and implies that worm infestation completely prevents immune malfunction, which is not supported by the evidence.

Choice C.

Worm infestations exacerbate the body’s immune reactions is not correct because it contradicts the new findings that worm infestation can relieve the effects of certain autoimmune disorders.

Choice D.

Lack of worm infestations is the cause of some autoimmune disorders is not correct because it overstates the findings and implies a causal relationship between lack of worm infestations and autoimmune disorders, which is not supported by the evidence.

Sodium bicarbonate neutralizes the acidity of chyme.

The pancreas secretes large amounts of sodium bicarbonate, which protects the duodenum by neutralizing the acid that comes from the stomach.

This compound helps neutralize stomach acid generated during the digestive process.

Choice A is incorrect because sodium bicarbonate is not a protease that digests carbohydrates.

Proteases are enzymes that break down proteins, while sodium bicarbonate is a chemical compound that helps neutralize stomach acid.

Choice B is incorrect because sodium bicarbonate does not stimulate the pyloric sphincter.

The pyloric sphincter is a ring of smooth muscle that separates the stomach from the duodenum and regulates the passage of partially digested food (chyme) into the small intestine.

Choice C is incorrect because sodium bicarbonate does not inhibit peristalsis.

Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract.

In DNA, the nitrogenous bases adenine (A) and thymine (T) pair together, while cytosine (C) and guanine (G) pair together.

Therefore, the complementary strand of the given DNA sequence 3' TCGATCGCA 5' would have the complementary nitrogenous bases as:

5’ AGCTAGCGT 3’

NOTE: The 5’ to 3’ direction of the complementary strand is opposite to that of the given strand.

Choice A.

3’ AGCTAGCGT 5’ is not correct because it is not complementary to the given strand.

Choice C.

5’ UCGAUCGCA 3’ is not correct because it contains uracil (U), which is a nitrogenous base found in RNA, not DNA.

Choice D.

3’ TCGUTCGCU 3’ is not correct because it also contains uracil (U), which is a nitrogenous base found in RNA, not DNA.

The glomerulus is the main filtering unit of the kidney.

It is formed by a network of small blood vessels (capillaries) enclosed within a sac called the Bowman’s capsule.

The blood supply to the glomerulus is provided via the afferent arteriole.

The blood then flows through the capillary network, where it gets filtered, and then leaves the glomerulus via the efferent arteriole.

Choice B.

Proximal tubule is not correct because it is where the ultrafiltrate collected in the Bowman’s space drains directly into.

Choice C.

Distal tubule is not correct because it is not mentioned in relation to blood exiting the glomerulus.

Choice D.

Afferent arteriole is not correct because it provides blood supply to the glomerulus.

A myocardial infarction affects the coronary blood vessels of the heart.

A myocardial infarction, commonly known as a heart attack, occurs when blood flow decreases or stops in the coronary artery of the heart, causing damage to the heart muscle 1.

Choice B is incorrect because the aorta is not a blood vessel of the heart.

The aorta is the main artery that carries oxygenated blood from the heart to the rest of the body.

Choice C is incorrect because the pulmonary blood vessels are not affected by a myocardial infarction.

The pulmonary blood vessels carry deoxygenated blood from the heart to the lungs.

Choice D is incorrect because the vena cava is not a blood vessel of the heart.

The vena cava is a large vein that carries deoxygenated blood from the body to the heart.

Amino acids have a unique structure consisting of an amino group (-NH3⁺) and a carboxyl group (-COO⁻) attached to a central carbon (called the α-carbon). At physiological pH (around 7.4), these functional groups often exist in their ionized forms:

• The amino group (-NH3⁺) is positively charged, acting as a proton acceptor (a base).
• The carboxyl group (-COO⁻) is negatively charged, acting as a proton donor (an acid).

This results in a zwitterion — a molecule with both a positive and a negative charge. Because amino acids can accept or donate protons depending on the pH of their environment, they have buffering capacity. This means they can resist changes in pH by stabilizing the concentration of hydrogen ions (H⁺).

Why Other Options Are Incorrect:

• A. Monosaccharides: These are simple sugars without ionizable functional groups, so they cannot act as buffers.
• B. Ribonucleotides and D. Deoxyribonucleotides: While nucleotides have phosphate groups that can donate protons, they lack the dual positive and negative functional groups necessary for the strong buffering effect seen in amino acids.

Therefore, amino acids are the correct choice because their zwitterionic nature provides them with excellent buffering capacity.

Proteins.

Proteins are made up of amino acids which are organic molecules that contain both an amine functional group (–NH2) and a carboxylic acid functional group (– COOH).

Choice A, Lipids, is not the correct answer because lipids are a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, triglycerides, phospholipids, and others.

They do not contain both an amine and carboxyl group.

Choice B, Chitin, is not the correct answer because chitin is a long-chain polymer of N-acetylglucosamine, a derivative of glucose.

It does not contain both an amine and carboxyl group.

Choice C, Cellulose, is not the correct answer because cellulose is an organic compound with the formula (C6H10O5)n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units.

It does not contain both an amine and carboxyl group.