Answer:
D. Calcium ions.
Explanation:
Here we are talking about the mechanism of muscle contraction. The most accepted theory of muscle contraction is sliding filament theory. It was given by Huxley and Huxley. During the process actin filaments slides over myosin filament by forming cross bridges. The sequence of events are as follows:
a. An action potential propagates through the motor nerve and reach the nerve endings on the muscle fiber at neuro-muscular junction.
b. Neurotransmitter called acetylcholine is released by the nerve endings.
c. Acetylcholine binds to the receptors on muscle fiber and opens the gated channels which causes flow of Na+ ions into the muscle fiber.
d. This influx of sodium ions initiates an action potential in the muscle fiber which reaches the T- tubules or transverse tubules. Here it causes the sarcoplasmic reticulum to release large amounts of calcium ion.
e. Calcium ions are responsible for initiating the attractive forces between actin and myosin filaments. Cross bridges are formed, actin slides over myosin causing the contraction of muscle.
Answer:
photosynthesis
Explanation:
Chloroplasts are found in plant cells its function is the process by which energy from the Sun is converted into chemical energy for growth. Also called photosynthesis.
Birds are mammals, dragonflies are insects
In the society of clones, human clone lacks traits necessary for true independence from "parent" cells.
<u>Explanation:</u>
Clone can be defined as an individual organism that was grown from a single body cell of it's parents and that clone is literally identical to it's parent from which it has grown.
In this society, a human clone lacks traits necessary for true independence from the "parent" cells. There is also a contrast that whether a clone is entitled by contrast to feel that a parent cell is an appropriate parent cell or not.
Answer:
Cell wall, chloroplast, and central vacuole
Explanation:
Cell wall, chloroplast, and central vacuole are present in a plant cell but not in the animal cell.
Nucleus, cell membrane, and cytoplasm present in both plant and animal cells.
