Correct Answer: B

Rationale: The correct answer is B because a decrease in natural predators can lead to an increase in the deer population as there are fewer predators to control their numbers. This explanation aligns with the situation described in the question, where the deer population has increased, causing issues for residents. Choice A is incorrect because an increase in food sources would not directly explain the increase in the deer population. Choice C is incorrect as it introduces a new factor of migration which is not mentioned in the question. Choice D is incorrect as an increase in hunting licenses sold would likely have the opposite effect on the deer population.

Correct Answer: D

Rationale: The epiglottis is a flap of tissue that covers the trachea during swallowing to prevent food and liquids from entering the airway. This action helps direct food into the esophagus, ensuring proper passage into the digestive system and avoiding potential choking or aspiration into the lungs. Choices A, B, and C are incorrect because the trachea connects the larynx to the bronchi, the esophagus connects the throat to the stomach, and the diaphragm is a muscle that plays a vital role in breathing by separating the thoracic and abdominal cavities, aiding in respiration.

Correct Answer: C

Rationale: The correct answer is C. RNA serves as a messenger that carries instructions from DNA for protein synthesis. It does not manufacture proteins directly from DNA (choice A), create bonds within DNA (choice B), or form the double helix structure of DNA (choice D). Therefore, the primary role of RNA is to convey information about the correct sequence of proteins to be synthesized based on the DNA sequences it receives.

Correct Answer: B

Rationale: The correct answer is B, 'Stomach.' The stomach is an organ of the digestive system responsible for breaking down food through mechanical and chemical digestion. In contrast, the thyroid, intestines, and pancreas are glands. The thyroid gland regulates metabolism through hormone secretion, the intestines aid in digestion and nutrient absorption, and the pancreas secretes digestive enzymes and hormones. Therefore, the stomach is functionally different from the other options as it is an organ involved in digestion, while the others are glands with specific secretory functions.

Correct Answer: D

Rationale: The atomic mass of an atom is the sum of the protons and neutrons in its nucleus. In this case, the atom has 2 protons and 4 neutrons, totaling 6 particles in the nucleus. Therefore, the approximate atomic mass of this atom is 6, making choice C incorrect. The number of electrons does not significantly contribute to the atomic mass, as they are much lighter and located in the electron cloud surrounding the nucleus. Choices A, B, and C are incorrect as they do not reflect the correct calculation of atomic mass based on protons and neutrons only.