1. The lymphatic system works closely with which other body system to fight infections?

A. Respiratory system
B. Digestive system
C. Immune system
D. Nervous system

Correct answer: A

Rationale: The correct answer is the Respiratory system. The lymphatic system and the respiratory system work closely together to fight infections. The respiratory system helps to filter out pathogens and other harmful substances from the air we breathe, while the lymphatic system produces and transports white blood cells (lymphocytes) that play a key role in the immune response against infections. This collaboration helps the body to defend against respiratory infections and maintain overall health.

2. Fingernails and toenails are made primarily of:

A. Collagen (Collagen is found in the dermis)
B. Keratin
C. Melanin (Melanin provides pigment, not structure)
D. Sebum (Sebum is an oily substance)

Correct answer: B

Rationale: The correct answer is B: Keratin. Fingernails and toenails are primarily made of a tough protein called keratin. Keratin is a fibrous structural protein that also makes up hair and the outer layer of skin. Collagen, as mentioned in option A, is found in the dermis of the skin and is responsible for providing strength and elasticity to the skin. Melanin, as in option C, is a pigment that gives color to the skin, hair, and eyes, but it does not contribute to the structure of nails. Sebum, as in option D, is an oily substance produced by the sebaceous glands in the skin to moisturize and protect the skin, but it is not a component of nails.

3. Which of the following is NOT a common symptom of lactose intolerance?

A. Gas
B. Bloating
C. Diarrhea
D. Nausea

Correct answer: D

Rationale: Rationale: A) Gas: Gas is a common symptom of lactose intolerance. When lactose is not properly digested, it can ferment in the colon, leading to the production of gas. B) Bloating: Bloating is another common symptom of lactose intolerance. The buildup of gas in the digestive system can cause bloating and discomfort. C) Diarrhea: Diarrhea is a common symptom of lactose intolerance. When lactose is not broken down in the small intestine, it can draw excess water into the colon, resulting in diarrhea. D) Nausea: Nausea is not a common symptom of lactose intolerance. While some individuals may experience mild stomach discomfort or cramps, nausea is not typically associated with lactose intolerance.

4. Which of the following is the main function of the kidneys?

A. To filter waste products from the blood
B. To produce urine
C. To regulate blood pressure
D. To produce hormones that help to control blood sugar levels

Correct answer: A

Rationale: Rationale: A) To filter waste products from the blood: The main function of the kidneys is to filter waste products, excess ions, and water from the bloodstream to form urine, which is then excreted from the body. This process helps maintain the body's internal environment by regulating the balance of electrolytes, fluid volume, and pH levels. B) To produce urine: While the kidneys do produce urine as a result of filtering the blood, the primary function is to filter waste products rather than solely producing urine. C) To regulate blood pressure: The kidneys do play a role in regulating blood pressure by controlling the volume of blood and the concentration of electrolytes in the body, but their main function is waste filtration. D) To produce hormones that help to control blood sugar levels: While the kidneys do produce hormones like erythropoietin and renin that play a role in various physiological processes, such as red

5. What is the function of introns in eukaryotic genes?

A. They code for protein sequences.
B. They are involved in gene regulation.
C. They are removed during mRNA processing.
D. They are non-functional remnants of ancient DNA.

Correct answer: C

Rationale: Rationale: A) Introns do not code for protein sequences. Exons are the segments of DNA that code for proteins. B) While introns can indirectly influence gene regulation, their primary function is not directly involved in gene regulation. C) Introns are non-coding regions of DNA that are transcribed into pre-mRNA but are removed during mRNA processing through a process called splicing. This allows only the exons to be included in the mature mRNA that will be translated into proteins. D) While introns were once thought to be non-functional remnants of ancient DNA, research has shown that they can have regulatory functions and play a role in gene expression.

6. In physics, what term describes the resistance of an object to changes in its motion?

A. Inertia
B. Momentum
C. Gravity
D. Kinetic energy

Correct answer: A

Rationale: Inertia is the term that describes the resistance of an object to changes in its motion. This property is described by Newton's First Law of Motion, which states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and in the same direction unless acted upon by an external force. Momentum (B) is the product of an object's mass and velocity, gravity (C) is the force that attracts objects towards each other, and kinetic energy (D) is the energy an object possesses due to its motion.