CBSE Questions for Class 9 Biology Tissues Quiz 8 - MCQExams.com

A. Correct option is (D)

 B. Explanation for the correct option.

1.    Haemoglobin is an iron-containing protein found in RBC.

2.    It is a tetrameric protein.

3.    It consists of two alpha and two beta subunits.

4.    It carries oxygen via blood to all parts of the body.

5.    At a time, it carries 4 oxygen molecules.

6.    Haemoglobin has a higher affinity for carboxyhaemoglobin than oxyhaemoglobin.

• Connective tissue is a type of tissue distributed throughout the body to form the supporting framework of the body and to bind together and support other tissues. It binds organs to other organs, muscles to bones, and bones to other bones.
• Muscles help in movement.
• Epithelial tissue forms the protective outer covering of the body and internal organs.
• Nerves help in the transmission of impulses to and from the central nervous system.

White blood cells (WBCs), also called leukocytes, are an important part of the immune system. These cells help fight infections by attacking bacteria, viruses, and germs that invade the body. White blood cells originate in the bone marrow but circulate throughout the bloodstream. There are five major types of white blood cells:

• Neutrophils
• Lymphocytes
• Eosinophils
• Monocytes
• Basophils

• Tendons are the tissues which connect muscles to bones.
• Ligaments connect one bone to other at joints and consist of dense regular connective tissues.
• Muscles are the organs that consists different types of tissues and are responsible for bodily movements by their attachment to bones through tendons.
• Cartilage is a flexible skeletal tissue that forms skeleton of embryo and serves to connect short bones together.

• Mature red blood cells are not nucleated to increase their surface area for carrying oxygen.
• Blood platelets like thrombocytes are involved in the clotting process.
• Erythropoiesis is the process of production of red blood cells or erythrocytes. This process takes place in the red bone marrow of long bones. Before birth, this process is taken care of by the liver and the spleen but after birth, the process of erythropoiesis is extensively carried out in the bone marrow.
• White blood cells are phagocytes of foreign matter.
• New red blood cells are constantly developing in the bone marrow.

• Neuron or nerve cells are the functional units of the nervous system. Each neuron has a cell body that encloses the nucleus and cytoplasm. 
• A number of processes arise from the cell body. These processes are called dendrites. In the given diagram P represents the dendrites. Dendrites play an important role in receiving nerve impulses from other neurons. 
• The cell body is the spherical part of the neuron that contains the nucleus and connects to the dendrites, which bring information into the neuron, and the axon, which sends information to other neurons.
  
• Myelin sheaths are sleeves of fatty tissue that protect the nerve cells. 
  
• The myelin sheath is regularly interrupted along the length of the axon by specialized regions called the nodes of Ranvier, which are necessary for the propagation of an action potential along the axon. The nodes of Ranvier are essential in the speed and timing of the delivery of impulses from one neuron to another.
  

• In the human body, the connective tissue is widely distributed. This tissue supports and connects the various body parts.  
• Bones are the major connective tissue that supports the entire body and protects the organs. 
• They are connected to each other by ligaments. Cartilage is present at the ends of the long bones which prevent the friction between the bones during movements. 
  Thus the correct answer is option D.