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.
The wrong part is a total of one :)
Answer;
Colloid
Fog is a colloid composed of water droplets in air.
Explanation;
-Fog is made up of condensed water droplets which are the result of the air being cooled to the point where it can no longer hold all of the water vapor it contains.
-A colloid is a heterogeneous mixture in which the dispersed particles are intermediate in size between those of a solution and a suspension. A fog is an example of a colloid as a beam of light can be easily seen passing through it.
<span>the degree of compactness of a substance.. Hope this helps</span>
F=ma
m=40 kg
a= unknown
f= 400 N
rearrange equation to f/m=a
so (400)/(40) = 10 m/s/s
