Which of the following are examples of positive correlation?
- A. As rainfall increases, plant stem length decreases.
- B. As rainfall increases, roots show longer length.
- C. When plotting a comparison of rainfall to plant length, the line trends to the lower right.
- D. When plotting a comparison of rainfall to plant length, the line trends to the upper right.
Correct Answer: D
Rationale: The correct answer is D. Positive correlation indicates that as one variable increases, the other variable also increases. In this case, when plotting a comparison of rainfall to plant length, if the line trends to the upper right, it shows a positive correlation where as rainfall increases, plant length also increases. Choices A, B, and C show either no correlation or negative correlation, as they describe scenarios where the variables move in different or opposite directions.
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Which of the following hormones is responsible for regulating blood sugar levels?
- A. Insulin
- B. Adrenaline
- C. Cortisol
- D. Melatonin
Correct Answer: A
Rationale: Insulin is the hormone responsible for regulating blood sugar levels by facilitating the uptake of glucose into cells. Insulin helps lower blood sugar levels by promoting the storage of glucose in the liver, muscle, and fat cells. Adrenaline, cortisol, and melatonin do not directly regulate blood sugar levels. Adrenaline is involved in the fight-or-flight response, cortisol is a stress hormone that affects metabolism, immune response, and anti-inflammatory actions, while melatonin regulates sleep-wake cycles.
What is the ultimate end product of glucose breakdown in glycolysis?
- A. ATP
- B. NADPH
- C. Pyruvic acid
- D. Oxygen
Correct Answer: C
Rationale: The ultimate end product of glucose breakdown in glycolysis is pyruvic acid. During glycolysis, glucose is broken down into pyruvic acid through a series of enzymatic reactions. ATP is produced as an energy carrier during glycolysis, but it is not the final end product. NADPH is not a direct product of glycolysis; it is mainly produced in the pentose phosphate pathway. Oxygen is not a product of glycolysis but is used as an electron acceptor in the electron transport chain of cellular respiration.
Which of the following is an example of a ball-and-socket joint?
- A. Knee
- B. Hip
- C. Elbow
- D. Wrist
Correct Answer: B
Rationale: The correct answer is B, Hip. The hip joint is a ball-and-socket joint, characterized by the spherical head of one bone (femur) fitting into the cup-like socket of another bone (pelvis). This structure allows for a wide range of motion in multiple directions, such as flexion, extension, abduction, adduction, and rotation. Choices A, C, and D are incorrect as the knee, elbow, and wrist joints are not ball-and-socket joints. The knee is a hinge joint, allowing flexion and extension movements. The elbow is a hinge joint that allows flexion and extension, while the wrist is a condyloid joint permitting flexion, extension, abduction, adduction, and circumduction movements.
Which of the following is not a biological macromolecule?
- A. Glycoproteins
- B. DNA
- C. Phospholipid
- D. Glucose
Correct Answer: D
Rationale: Glucose is a monosaccharide, which is a simple sugar and not a macromolecule. Glycoproteins, DNA, and phospholipids are all examples of biological macromolecules. Glycoproteins are proteins covalently bonded to carbohydrates, DNA is a nucleic acid, and phospholipids are lipids that contain a phosphate group.
What is the role of platelets in the blood?
- A. Transport oxygen
- B. Fight infection
- C. Produce antibodies
- D. Clot blood
Correct Answer: D
Rationale: Platelets play a crucial role in blood clotting by forming clots to help stop bleeding. While red blood cells transport oxygen, white blood cells fight infection, and immune cells produce antibodies, platelets specifically function to prevent excessive bleeding by forming clots. Therefore, the correct answer is D. Choices A, B, and C are incorrect as they describe functions of other components of the blood, not platelets.