1. Which muscular pouch in the upper left abdomen stores food after swallowing and begins mechanical and chemical digestion?

A. Esophagus
B. Stomach
C. Small intestine
D. Large intestine

Correct answer: B

Rationale: The correct answer is B: Stomach. The stomach is the muscular pouch in the upper left abdomen that stores food after swallowing. It is responsible for beginning both mechanical and chemical digestion processes. Once food enters the stomach, it is mixed with gastric juices and enzymes that break down the food into smaller particles. The stomach also contracts and relaxes to further mix the food with digestive juices. The esophagus is a tube that connects the throat to the stomach and does not store food or participate in digestion. The small intestine and large intestine are parts of the digestive system, but they are not muscular pouches in the upper left abdomen responsible for storing and digesting food.

2. The Becquerel (Bq) is the designated unit for quantifying:

A. Electron volt (eV) measurements of energy
B. Radioactivity
C. Electric charge (Coulombs)
D. Force (Newtons)

Correct answer: B

Rationale: The Becquerel (Bq) is the designated unit for quantifying radioactivity. Radioactivity is the measure of the rate at which radioactive atoms undergo nuclear decay and emit radiation. One Becquerel is equal to one nuclear decay event per second. This unit is named after Henri Becquerel, the scientist who discovered radioactivity. Therefore, option B, 'Radioactivity,' is the correct answer. Electron volt (eV) measurements of energy are quantified using a different unit, electric charge is measured in Coulombs, and force is quantified in Newtons, making them incorrect choices for this question.

3. What is the feedback mechanism in the endocrine system that helps maintain hormone balance?

A. Positive feedback, where a hormone stimulates its own release
B. Negative feedback, where a hormone suppresses its own release
C. Cascade effect, where one hormone triggers the release of another
D. Dual hormone system, where two hormones work together

Correct answer: B

Rationale: The correct answer is B: Negative feedback, where a hormone suppresses its own release. In the endocrine system, negative feedback is a crucial mechanism that helps maintain hormone balance. When hormone levels rise, they signal the body to decrease further hormone production, preventing an excess. This ensures that hormone levels stay within a narrow range, promoting stability and homeostasis. Positive feedback (option A) would lead to an amplification of hormone release, which is not ideal for maintaining balance. Cascade effect (option C) involves a sequential activation of hormones but does not directly regulate hormone levels. Dual hormone system (option D) refers to two hormones working together but doesn't specifically address the feedback mechanism for maintaining hormone balance.

4. Electrons occupy specific energy levels around the nucleus, but not in fixed orbits. This concept is captured by the:

A. Bohr model
B. Quantum mechanical model
C. Lewis structure
D. Octet rule

Correct answer: B

Rationale: Quantum mechanical model. Unlike the Bohr model with its defined electron paths, the quantum mechanical model uses probability distributions to describe electron locations within energy levels.

5. Which of the following is NOT a type of intermolecular force?

A. Hydrogen bonding
B. Dipole-dipole interactions
C. Ionic bonding
D. London dispersion forces

Correct answer: C

Rationale: Ionic bonding is a type of intramolecular force, holding ions together within an ionic compound. Intermolecular forces are responsible for the interactions between individual molecules.

6. Histamine, released during an allergic reaction, causes symptoms like:

A. Fever and fatigue
B. Runny nose and itchiness
C. Muscle aches and joint pain
D. Cough and shortness of breath

Correct answer: B

Rationale: The correct answer is B: 'Runny nose and itchiness.' Histamine is a chemical released by the body during an allergic reaction. It causes various symptoms such as itching, sneezing, runny nose, and watery eyes. These symptoms are commonly associated with allergic reactions like hay fever or hives. Fever and fatigue (option A) are not directly caused by histamine release. Muscle aches and joint pain (option C) are not typical symptoms of histamine release during an allergic reaction. Cough and shortness of breath (option D) are more commonly associated with asthma or respiratory allergies rather than histamine release.