OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

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Study for the OCR GCSE Biology Exam. Use multiple choice questions and quiz flashcards with explanations and hints. Excel in your exams!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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What components make up blood?

Only red blood cells
Plasma, platelets, red blood cells, and white blood cells
Plasma and red blood cells
Plasma, hemoglobin, and white blood cells

The correct answer is: Plasma, platelets, red blood cells, and white blood cells

Blood is composed of several key components that each play essential roles in maintaining health and proper physiological function. The correct response identifies that blood consists of plasma, platelets, red blood cells, and white blood cells. Plasma serves as the liquid medium of blood, making up about 55% of its volume. It contains water, electrolytes, hormones, nutrients, and waste products, facilitating the transportation of these substances throughout the body. Red blood cells, or erythrocytes, are responsible for carrying oxygen from the lungs to other tissues and returning carbon dioxide from the tissues to the lungs. White blood cells, or leukocytes, play a crucial role in the immune system, defending the body against infections and foreign invaders. Platelets are cell fragments vital for blood clotting, helping prevent excessive bleeding when injuries occur. The presence of all these components is essential for the various functions that blood performs, which include transportation of gases and nutrients, immune responses, and clotting mechanisms. Therefore, the completeness of this answer captures the complexity of blood's structure and its functions within the human body.