Tissues — Set 3
Biology · ऊतक · Questions 21–30 of 40
Which tissue is responsible for the movement of food in plants?
Correct Answer: C. Phloem
Phloem tissue transports nutrients produced during photosynthesis to various parts of the plant. This process is known as translocation and can occur in both upward and downward directions. It consists of sieve tubes, companion cells, phloem parenchyma, and phloem fibers.
The basic structural and functional unit of bone tissue is the?
Correct Answer: B. Osteon
Bone is a hard connective tissue with a matrix composed of calcium and phosphorus compounds. The functional unit of compact bone is called an osteon or Haversian system. Osteocytes are the mature bone cells found within this rigid matrix.
Which of the following is an example of an involuntary muscle?
Correct Answer: B. Iris muscle of the eye
Involuntary muscles, like those in the iris of the eye, cannot be controlled by conscious will. These are also found in the alimentary canal and blood vessels. They are usually smooth or non-striated in appearance.
Which of the following tissues is most abundant in the human body by weight?
Correct Answer: B. Connective tissue
Connective tissue is the most widespread and abundant tissue type in animal bodies. It serves diverse roles including binding, support, protection, and transport. Examples include blood, bone, cartilage, and adipose tissue.
Which tissue covers the external surface of the body and lines the internal cavities?
Correct Answer: A. Epithelial tissue
Epithelial tissue forms a continuous sheet of cells that serves as a protective barrier. It regulates the exchange of materials between the body and the external environment. The cells are tightly packed with very little intercellular matrix.
What is the primary function of stomata found in the leaf epidermis?
Correct Answer: D. Gas exchange
Stomata are small pores in the leaf epidermis guarded by two kidney-shaped guard cells. They are primarily responsible for the exchange of gases like oxygen and carbon dioxide. They also facilitate the process of transpiration in plants.
Which cells are responsible for the clotting of blood during an injury?
Correct Answer: D. Platelets
Platelets, also known as thrombocytes, are small cell fragments involved in the blood clotting mechanism. They help prevent excessive blood loss by forming a physical plug at the site of injury. This process is vital for maintaining the integrity of the circulatory system.
Which of the following tissues has cells that are dead at maturity?
Correct Answer: B. Sclerenchyma
Sclerenchyma cells lose their protoplasm and become dead as they mature. This allows them to focus entirely on providing mechanical strength to the plant. Lignin, a chemical cement, makes their cell walls thick and impermeable.
The layer of cells that protects the trunk of an old tree is called?
Correct Answer: D. Cork
As a tree grows older, the outer protective tissue is replaced by a secondary meristem called cork. Cork cells are dead and arranged compactly without intercellular spaces. They contain a substance called suberin that makes them impervious to water and gases.
Which connective tissue joins two bones together?
Correct Answer: D. Ligament
Ligaments are very elastic connective tissues that connect one bone to another at joints. They have great strength but contain very little matrix. Overstretching a ligament results in a common injury known as a sprain.