False. Phospholipids do not make up most of the lipid present both in the body and in food.
Answer:
When you put food in your mouth, your teeth break the food into smaller pieces, and the salivary glands under your tongue and on the sides and roof of your mouth release saliva. This saliva mixes with your food to make it easier to swallow.
Explanation:
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.
Natural selection is what caused them to change
In interspecies competition, two species use the same limited resource. Competition has a negative effect on both of the species (-/- interaction).
A species' niche is basically its ecological role, which is defined by the set of conditions, resources, and interactions it needs (or can make use of).
The competitive exclusion principle says that two species can't coexist if they occupy exactly the same niche (competing for identical resources).
Two species whose niches overlap may evolve by natural selection to have more distinct niches, resulting in resource partitioning.
