1. Which skin condition is characterized by patches of inflamed, reddened skin and is often triggered by allergens or stress?

A. Eczema
B. Psoriasis
C. Acne
D. Vitiligo

Correct answer: A

Rationale: The correct answer is A: Eczema. Eczema is a skin condition characterized by patches of inflamed, reddened skin that can be triggered by allergens or stress. It is a chronic condition that can cause itching and discomfort. Psoriasis (option B) is a different skin condition characterized by red, scaly patches on the skin. Acne (option C) is a common skin condition characterized by pimples and clogged pores. Vitiligo (option D) is a condition where the skin loses its pigment, resulting in white patches. Therefore, eczema best fits the description provided in the question.

2. What can be inferred about the water management systems in Petra?

A. They were unreliable and contributed to the city's decline.
B. They were simple and ineffective compared to modern systems.
C. They were sophisticated and played a crucial role in Petra's survival.
D. They were destroyed by explorers when Petra was rediscovered.

Correct answer: C

Rationale: The passage highlights the "elaborate" water systems, suggesting their complexity and importance.

3. What is the name of the radioactive isotope commonly used in medical imaging techniques like PET scans?

A. Uranium-235
B. Plutonium-239
C. Potassium-40
D. Fluorine-18

Correct answer: D

Rationale: Fluorine-18 is the radioactive isotope commonly used in medical imaging techniques like PET scans. It is often used in the form of fluorodeoxyglucose (FDG) to detect areas of increased metabolic activity in the body, such as in cancer cells. Uranium-235 and Plutonium-239 are not typically used in medical imaging, and Potassium-40 is a naturally occurring radioactive isotope found in the human body but is not commonly used in medical imaging techniques.

4. The fluid-filled, jelly-like substance within the cell that suspends the organelles is called the:

A. Nucleus
B. Cytoplasm
C. Plasma membrane
D. Golgi apparatus

Correct answer: B

Rationale: The correct answer is B: Cytoplasm. Cytoplasm is the fluid-filled, jelly-like substance within the cell that suspends the organelles. It is where many cellular processes take place, such as metabolism and protein synthesis. The nucleus (option A) is the organelle that contains the cell's genetic material, the plasma membrane (option C) is the outer boundary of the cell that regulates what enters and exits the cell, and the Golgi apparatus (option D) is involved in processing and packaging proteins. Understanding the functions of each organelle is crucial in recognizing that the cytoplasm is the correct answer in this context.

5. What is the main function of the gallbladder?

A. To store and concentrate bile
B. To produce digestive enzymes
C. To absorb nutrients
D. To neutralize stomach acid

Correct answer: A

Rationale: Rationale: The gallbladder is a small organ located beneath the liver that plays a crucial role in the digestive system. Its main function is to store and concentrate bile, a digestive fluid produced by the liver. Bile is released from the gallbladder into the small intestine to help with the digestion and absorption of fats. The gallbladder acts as a reservoir for bile, allowing it to be released in a controlled manner when needed to aid in the digestion of fatty foods. Therefore, option A is the correct answer as it accurately describes the main function of the gallbladder.

6. Which of the following numbers is a perfect square?

A. 10
B. 12
C. 15
D. 16

Correct answer: D

Rationale: A perfect square is a number obtained by squaring an integer. 16 is the result of squaring 4 (4 x 4 = 16). The other answer choices are not the product of squaring any whole number.