Which of the following summarizes a change that takes place as a solid turns to a liquid?

 

The atomic number of an atom is equal to the number of protons in its nucleus.

In this case, the atom has 12 protons, so its atomic number is 12.

Choice A, 24, is not the correct answer because it represents the sum of the number of protons and neutrons in the atom’s nucleus, which is known as the mass number.

Choice C, 1, is not the correct answer because it does not represent the number of protons in the atom’s nucleus.

Choice D, 144, is not the correct answer because it represents the square of the mass number and does not represent any property of the atom.

Plasma B cells.

Antibodies are produced by specialized white blood cells called B lymphocytes (or B cells).

When an antigen binds to the B-cell surface, it stimulates the B cell to divide and mature into a group of identical cells called a clone.

The mature B cells, called plasma cells, secrete millions of antibodies into the bloodstream and lymphatic system.

Choice A, Natural killer cells, is not the correct answer because natural killer cells are a type of white blood cell that play a major role in the host-rejection of both tumors and virally infected cells.

Choice B, Cytotoxic T-cells, is not the correct answer because cytotoxic T-cells are a type of white blood cell that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways.

Choice D, Helper T-cells, is not the correct answer because helper T-cells are a type of white blood cell that play an important role in the immune system by helping other white blood cells fight infections.

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.

Other scientists can validate or disprove the findings.

It is important for new scientific findings to be published so that other scientists can review the research and either validate or disprove the findings.

This process of peer-review helps to ensure the accuracy and reliability of scientific research.

Choice A.

Scientists will get paid if their findings are published is not correct because while some scientists may receive funding or grants for their research, the primary goal of publishing scientific findings is not for financial gain.

Choice B.

Publishing findings will help scientists become more biased is not correct because the goal of publishing scientific findings is to share information and promote transparency, not to promote bias.

Choice D.

This prevents other scientists from performing similar tests is not correct because publishing scientific findings allows other scientists to build upon the research and perform further tests to validate or disprove the findings.

The pulmonary veins are the vessels that carry oxygenated blood from the lungs to the left atrium of the heart.

Choice A is not correct because the superior vena cava carries deoxygenated blood from the upper body to the right atrium of the heart.

Choice B is not correct because the inferior vena cava carries deoxygenated blood from the lower body to the right atrium of the heart.

Choice C is not correct because the pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs.

Bag mass change is the dependent variable in this experiment.

In an experiment, the dependent variable is the variable that is being measured and is expected to change in response to changes in the independent variable(s).

In this case, the bag mass change is being measured and is expected to change in response to changes in the independent variable (sucrose concentration).

Choice A is incorrect because duration is not a variable in this experiment.

Choice B is incorrect because temperature is not a variable in this experiment.

Choice D is incorrect because sucrose concentration is an independent variable, not a dependent variable.

An independent variable is a variable that is manipulated by the experimenter to see how it affects the dependent

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.

The best reason for the prolonged preservation of the body is that it was frozen in the cold temperature of the Alps shortly after he died and remained frozen until it was found.

Freezing can preserve a body by slowing down or stopping the decomposition process.

Choice A is not correct because the food that the person ate would not have contained toxins that killed the bacteria that would have otherwise destroyed the body.

Choice B is not correct because the arrow wound would not have caused blood to flow out of the body in a way that would have cleared enzymes that break down tissue from the body.

Choice D is not correct because ultraviolet rays at high altitude would not have caused all of the body’s molecules to be preserved.

The corpus luteum is a structure that develops in the ovary after an egg has been released.

It secretes the hormone progesterone, which prepares the uterus for a fertilized egg to implant and helps maintain the uterine lining during pregnancy1.

Choice A.

Umbilical cord is not correct because it is a structure that connects the developing fetus to the placenta and provides nutrients and oxygen to the fetus, but does not secrete hormones.

Choice C.

Oviduct is not correct because it is a tube that transports eggs from the ovary to the uterus, but does not secrete hormones.

Choice D.

Oocyte is not correct because it is an immature egg cell, but does not secrete hormones.