Answer:
A new mutation
Explanation:
A mutation refers to the random changes in the DNA of organisms. A mutation changes the allele and genotype frequencies by the introduction of a new allele in the gene pool.
However, mutations are not the major factor responsible for changes in the gene pool of a population as mutations are rare. The rate of mutations is very slow and does not allow it to serve as a major factor to change the allele and genotype frequencies.
Answer:
The complex eukaryotic cell ushered in a whole new era for life on Earth, because these cells evolved into multicellular organisms. Evidence supports the idea that eukaryotic cells are actually the descendents of separate prokaryotic cells that joined together in a symbiotic union.
Neurons, also known as nerve cells, send and receive signals from your brain. While neurons have a lot in common with other types of cells, they’re structurally and functionally unique.
They are located in the liver the wall of the sinusoids.
Answer: movement is always voluntary
Explanation:
Muscles are contractile:
- Contractility is the ability of muscle cells to forcefully shorten. Think of having the ability to flex a muscle.
Muscles are excitable:
- Excitable tissue can conduct or transmit electrical impulses. Basically, it can react to stimulus, which may be delivered from a motor neuron or a hormone. For example, the hormone epinephrine helps muscles to produce force.
Muscles respond to stimulus:
- well since muscles are an excitable tissue, they can react to stimulus. (see answer above)
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Muscle movement is NOT always voluntary:
- Some muscle movement is voluntary, which means it is under conscious control. For example, a person decides to open a book and read. Other movements are involuntary, meaning they are not under conscious control, such as the contraction of your pupil in bright light, breathing, blinking, your heart beating, etc.
- Therefore, the correct answer is:
movement is always voluntary
hope this helps :)
