A Level Biology Practice Exam

What is the role of blood in the body?

1. To provide support to the body structure

2. To transmit electrical signals between neuron cells

3. To carry nutrients and gases to and from tissues

4. To facilitate hormonal control throughout the body

The correct answer is: To carry nutrients and gases to and from tissues

Blood plays a crucial role in transporting various substances throughout the body, which makes it essential for maintaining homeostasis and supporting the function of different organs and systems. It carries nutrients, such as glucose and amino acids, from the digestive tract to cells, where they are utilized for energy and building proteins. Additionally, blood transports oxygen from the lungs to tissues and carbon dioxide from tissues back to the lungs for exhalation, facilitating respiration. By serving as a medium for these substances, blood also helps regulate temperature and pH levels and contributes to the body's defense mechanisms through the transport of immune cells. While the roles of providing structural support, transmitting electrical signals, and facilitating hormonal control are important, they do not encompass the primary function of blood as effectively as the transport of nutrients and gases does. Thus, the correct answer highlights the fundamental physiological tasks performed by blood in the body's overall functioning.