teas 7 science practice - Nurselytic

Correct Answer: C

Rationale: Density is the measure of the mass of a substance per unit volume and is commonly expressed in kilograms per cubic meter. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and volume is the amount of space an object occupies. In this context, density is the correct term for expressing the measure of mass per unit volume, making it the most appropriate choice among the options provided.

Correct Answer: A

Rationale: Magnesium is the correct answer. It is essential for the formation of chlorophyll, the green pigment in plants that is crucial for photosynthesis. Chlorophyll absorbs sunlight and uses its energy to convert carbon dioxide and water into glucose and oxygen. Iron, copper, and zinc do not play a direct role in the green color of leaves. Iron is more related to processes like electron transport, copper is involved in enzyme functions, and zinc contributes to the synthesis of plant growth regulators.

Correct Answer: B

Rationale: The correct answer is the Mitral valve. The mitral valve is located between the left atrium and the left ventricle of the heart. Its function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction.
Choice A, the Tricuspid valve, is incorrect as it is located between the right atrium and right ventricle.
Choice C, the Aortic valve, and
Choice D, the Pulmonic valve, are also incorrect as they are involved in the circulation of blood leaving the heart rather than preventing backflow within the atria and ventricles.

Correct Answer: B

Rationale:
A) This statement is incorrect. RNA and DNA have different structures and functions. RNA is involved in protein synthesis and other cellular processes, while DNA stores genetic information.
B) This statement is correct. RNA is typically single-stranded, while DNA is double-stranded, forming a double helix structure.
C) This statement is correct. RNA contains ribose sugar in its backbone, while DNA contains deoxyribose sugar.
D) This statement is incorrect. RNA contains adenine, guanine, cytosine, and uracil, while DNA contains adenine, guanine, cytosine, and thymine.
Choice B is the correct answer as it accurately describes one of the key differences between RNA and DNA, emphasizing their structural disparity in terms of single-strandedness for RNA and double-strandedness for DNA.

Choices A, C, and D contain inaccuracies regarding the structural and compositional distinctions between RNA and DNA, making them incorrect choices.

Correct Answer: D

Rationale: The waste product of protein digestion is ammonia. Protein digestion breaks down proteins into amino acids, and during this process, ammonia is produced. Ammonia is toxic and needs to be converted into urea in the liver for excretion via urine. Glucose is a product of carbohydrate digestion, amino acids are building blocks of proteins, and fatty acids are the end products of fat digestion.
Therefore, the correct answer is ammonia.