1. What is the primary function of the epiglottis in the respiratory system?

A. Filtration of air
B. Production of mucus
C. Prevention of food entering the trachea
D. Oxygen exchange in the alveoli

Correct answer: C

Rationale: The primary function of the epiglottis in the respiratory system is to prevent food from entering the trachea. When we swallow, the epiglottis covers the opening to the trachea, directing food and liquids to the esophagus instead of the airway. This action helps to protect the respiratory system from foreign objects that could obstruct airflow and cause choking or aspiration pneumonia. Filtration of air and production of mucus are functions associated with other respiratory structures like the nasal passages and bronchial tubes, while oxygen exchange in the alveoli occurs in the lungs, not the epiglottis.

2. How many bones are there in the adult human skeleton?

A. 126
B. 206
C. 300
D. 525

Correct answer: D

Rationale: The correct answer is D: 525. The adult human skeleton consists of 206 bones. However, when accounting for individual bones, many of them are paired (like the ribs and vertebrae), bringing the total count to 206 individual bones but 525 in total when considering pairs. This includes bones in the skull, spine, ribs, arms, hands, pelvis, legs, and feet. So, while there are 206 individual bones, the total number of bones in the adult human skeleton is 525 when considering pairs.

3. What part of speech is the underlined word in the sentence "The students eagerly awaited the results"?

A. Verb
B. Noun
C. Adjective
D. Adverb

Correct answer: B

Rationale: Option B identifies "results" as the direct object of the verb "awaited," making it a noun.

4. A guitar string vibrates at a fundamental frequency of 440 Hz. What is the frequency of the second harmonic (first overtone)?

A. 220 Hz
B. 440 Hz
C. 880 Hz
D. 1760 Hz

Correct answer: C

Rationale: Harmonics have frequencies that are multiples of the fundamental frequency. The second harmonic has a frequency twice the fundamental, so it's 440 Hz * 2 = 880 Hz.

5. The phrase "green alternative" suggests that bioremediation is...

A. The most economical option for plastic cleanup.
B. Faster and more efficient than traditional methods.
C. Environmentally friendly and less harmful than other solutions.
D. More aesthetically pleasing than existing approaches.

Correct answer: C

Rationale: The passage contrasts bioremediation with "traditional methods," explicitly linking it to being environmentally friendly.

6. The term that refers to the specific role and position an organism occupies within an ecosystem is called a:

A. Habitat
B. Niche
C. Population
D. Biome

Correct answer: B

Rationale: Rationale: A) Habitat refers to the specific physical environment where an organism lives, including the biotic and abiotic factors present. While the habitat is important for an organism's survival, it does not encompass the specific role and interactions of the organism within the ecosystem. B) Niche refers to the specific role and position an organism occupies within an ecosystem, including its interactions with other organisms and its physical environment. This includes the organism's feeding habits, behavior, preferred habitat, and how it obtains resources. The niche of an organism is crucial in determining its impact on the ecosystem and its relationships with other species. C) Population refers to a group of individuals of the same species living in a specific area and interacting with each other. While populations play a role in ecosystems, they do not specifically describe the role and position of an individual organism within the ecosystem. D) Biome refers to a large geog