Are specialized cells that generate and conduct electrical impulses throughout the body. are the components of blood that protect against pathogens and aid in blood clotting. are specialized cells that transport, protect, absorb, secrete, and provide sensory signals. are the components of blood that carry oxygen throughout the body. are elongated cells that have the ability to contract.

The correct answers are as follows:
1. NEURONS: Are specialized cells that generate and conduct electrical impulses throughout the body.
Neurons are the nerve cells that are the basic building block of the nervous system. Their major function is to transmit information round the body. There are different type of neurons that carry information to different part of the body. There are three basic part to every neuron, these are the dendrites, the cell body and the axon.
2. WHITE BLOOD CELLS: Are components of blood that help protect against pathogens and aid in blood clotting.
White blood cells refers to the cells of the immune system, which help the human body to fight against all manner of infection causing pathogens. White blood cells are produced in the bone marrow and they form about 1% of the total blood volume. A low white blood cell count is usually as a result of presence of infection.
3. EPITHELIAL CELLS: Are specialized cells that transport, protect, absorb, secrete and provide sensory signals.
Epithelial cells are specialized cells that are found in many organs. They have similar structural properties especially in term of arrangement and the cohesiveness among them. They are specialized cells for absorption, secretion and they can also act as barrier.  
4. RED BLOOD CELLS: Are the component of the blood that carry oxygen throughout the body.
Red blood cells are the cellular component of the blood, which are responsible for transporting oxygen to every cells in the body. The cells carry fresh oxygen from the lungs and transport it to all parts of the body, they also collect carbon dioxide and transport it to the lung for breathing out. The red blood cells are manufacture in the bond marrow and the longest that a red blood cell can live is 120 days.  
5. MUSCLE CELLS: Are elongated cells that have the ability to contract. 
Muscle cells are made up of myosin and actin, which are protein filaments that slide past one another in order to produce contractions, which changes the length and shape of the cell. Muscles cells are largely responsible for maintaining and changing posture, locomotion and movement of internal organs. There are three basic types of muscles, they are skeletal, cardiac and smooth muscles. 

Spherical shaped cell might increase the surface area and decrease the volume.