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.
Although not specified, I am assuming that you want to identify the different variables and groups of this case. To answer this, the different typical factors that make up an experimental set up include: 1) dependent and 2) independent variables; 3) controlled variables; as well as the 4) control and 5) experimental group.
The dependent variable in this case is: the size of the population. While the independent variable is: the habitat space. Controlled variables in this experiment include: type and amount of food, cleanliness of the aquarium, and water temperature. The experimental group are simply the fish being observed. There are no controlled groups in this case depending on your definition. Controlled groups are usually the reference point or standard in experimental setups but this experiment wants to look at the differences of the goldfish with each other and not necessarily to a one particular goldfish and hence no controlled group.
The dependent variable is called as such because it is the one that changes depending on the factors given and is usually the one being observed. The independent variable is named as such because it remains the same throughout the experiment.
They produce many fish with food which is positive, but the negative impact they can have is when there are too many nutrients available phytoplankton can grow out of control, in which they will produce harmful algae blooms that are toxic and can harm sea life.
Answer:
Plants are multicellular eukaryotes. They have organelles called chloroplasts and cell walls made of cellulose.
Plants also have specialized reproductive organs.
Almost all plants make food by photosynthesis.
Life as we know it would not be possible without plants.
Answer:
Newton's Second Law of Motion states that when a force acts on an object, it will cause the object to accelerate.
Example:
#1. When you hit a baseball, it accelerates. It does not remain inactive.
#2. When wind blows a leaf off of a tree, it falls to the ground. It does not float in the air.
