The correct answer is A. Sunspots
Explanation:
The Sun is the star that is the center of the Solar system where Earth is located and that is mainly composed of hydrogen, helium and other elements such as oxygen, carbon or iron. In terms of the photosphere or the outer shell of the Sun this is a plasma layer that is mainly observed as uniform in color, but also presents dark areas that are called sunspots, these are cooler areas in the surface of the sun that exist as a result of the magnetic field of the sun; additionally, this can appear individually or in groups which are called Sunspot Groups. Therefore, the dark, cooler areas on the sun's surface are called Sunspots.
b. an allele that is found on many genes
c. an allele that mutates with each generation
d. an allele present in all members of a population?
All humans are homozygous for alleles known as fixed alleles. Of course, many human characteristics are malleable. Height, eye color, and hair color are all variable. Thus, option D is correct.
An allele in which there are no other alleles for this location in the population, since everyone in the studied population is homozygous for it.
Genetic variety may be hampered by genetic drift, which may cause gene variations to completely disappear. Additionally, it can make previously uncommon alleles common and even fixed.
An allele is said to be fixed if it is the only variant of that gene in the whole population.
All individuals in the population have homozygosity for a fixed allele. Typically, the term “allele” refers to one alternative gene among many that could exist for a specific DNA region.
Therefore, an allele present in all members of a population.
Learn more about fixed allele here:
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B. amylase
C. trypsin
B) It contains a methyl group bonded to a positively charged sulfur atom.
C) It contains a methyl ether.
D) it contains a methyl group bonded to an aromatic ring.
E)It contains a Br bonded to a phosphorus atom.
b.more of the available freshwater is stored in glaciers and icecaps
c.governments have banned the use of freshwater in rivers and springs
d.the demand for freshwater has increased due to population growth
Answer:
D
Explanation:
An action potential in a muscle cell is initiated by acetylcholine, which binds to receptors on the muscle cell membrane, causing depolarization. This triggers voltage-gated sodium channels to open, allowing sodium influx into the cell, which propagates the action potential. The action potential then leads to muscle contraction.
An action potential on a muscle cell is initiated through a complex sequence of events. First, a neurotransmitter called acetylcholine (ACh) is released from the motor neuron and binds to receptors on the muscle cell membrane or sarcolemma. This binding opens up a channel in the ACh receptor, allowing positively charged sodium ions to enter the muscle fiber.
This ion movement causes the muscle fiber to depolarize, or become less negative, changing the membrane potential. As the membrane depolarizes, another set of ion channels, the voltage-gated sodium channels, are activated and trigger an influx of more sodium ions into the muscle fiber.
This flooding of sodium ions propagates an action potential, or electrical signal, across the entire muscle cell membrane. This action potential then interacts with the sarcoplasmic reticulum to release calcium ions, leading to muscle contraction.
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