Answer:
Myelination
Explanation:
The covering of myelin around the axons is called the myelin sheath. This myelin sheath helps in transfer of information faster and also in complex processes of the brain. The process of myelination begins in the PNS (peripheral nervous system).
The myelinated section are seperated from each other with a gap called nodes of ranvier. Glial cells (oligodendrocytes) forms the myelin sheath in the central nervous system and schwann cells (glial cells) forms the myelin sheath in peripheral nervous system. The propagation of electrical impulse in the myelinated fibers is by saltatory conduction that is from one node to another.
Answer:
1. Muscle Fibers
2. Bones
3. Joints
Explanation:
Muscle tissue is made of muscle fibers. The plasma membrane of a muscle fiber is called sarcolemma while its cytoplasm is known as sarcoplasm. Muscle cells are characterized by the presence of specialized endoplasmic reticulum which is called sarcoplasmic reticulum.
Muscle cells exhibit contractility and extensibility. The ability of muscle cells to shorten their length forcibly in response to a stimulus is their contractility. Muscle fibers have the ability to extend and shorten themselves.
Extension and contraction of muscle fibers are responsible for the movement of the human body and its parts.
Muscles are attached to bones via tendons which in turn are the fibrous connective tissues. Muscles are also part of our joints where they assist in the movement by pulling the bones as well as stabilize and strengthen the joints.
Answer:
The correct answer is option A. "The contents of blood come into closer contact with tissues in a closed system than an open system".
Explanation:
In a closed circulatory system, the blood has an specific path, circulating from arteries to veins and to smaller blood vessels throughout the body. This is in contrast with open circulatory systems at which the blood is not contained in arteries or veins but it suffuses the body. A closed circulatory system have many advantages over open circulatory system, however in a closed circulatory system the contents of blood are not into closer contact with tissues in than an open system. Actually, in an open circulatory system the blood is in closer contact with tissues.
Answer:
Sand
Explanation:
Space, water, energy, and air are all needed for an organism to survive. Sand is just somewhere an organism could accustom to live in that environment.
