Mutation is the only evolutionary mechanism that does little to change allele frequencies.
Answer:
What can be noticed about the ligands and their receptor is that the configuration of both coincide, as a key would with its lock, which demonstrates the specificity of a receptor by its ligand.
Explanation:
A <u>ligand</u> corresponds to a molecule considered a signal or a messenger, while the <u>receptor</u> is a protein on the cell surface, with the capacity to accept a ligand.
Ligands and receptors constitute pairs that complement each other, so that <u>each receptor can bind to a specific ligand</u>, similar to what happens with a key and a lock.
Once the ligand-receptor complex is formed, changes occur inside the cell, which define a certain effect.
Answer:
c) Combustion of fossil fuels
Explanation:
Burning of fossil fuels is the main cause of increasing carbondioxide concentration in the environment which results in air pollution. This increase in carbondioxide concentration absorbed more heat energy from reflected solar radiation which increases the temperature of earth surface causes global warming. Due to this global warming, snow melting occurs on the poles of the earth which increases sea level.
Amino acids are acids on one hand, and a base on the other hand.
<h3>What is an acid?</h3>
An acid is a substance that produces hydrogen or hydroxonium ions as the only positively charged ion when it ionizes.
All amino acids have an amine group -
and a carboxylic group -
.
The carboxylic group ionizes such that:

The presence of the amine group enables amino acids to also act as a base.
More on amino acids can be found here: brainly.com/question/14583479
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<span>Here are some advantages:
1. it can create new varieties of good crops.
2. it allows for higher profit.
3. it does not have a issue of safety.
4. it helps eliminate diseases
5. it can produce fitter and stronger animals
Here are some disadvantages:
1. it can lead to a loss of species variety
2. it doesn't have control over genetic mutations
3. it brings discomfort to animals
4. it can create offspring with different traits
5. it poses some environmental risks</span>