Natural regeneration of forests and woodlands is the process by which new trees grow from seeds that have fallen and germinate where they have fallen. The biggest problem with natural regeneration is that is unpredictable. As a result, it cannot be used for commercial farming. For most of the last two or three hundred years, forests and woodlands have restocked by using transplants grown in nurseries. The young trees are planted in equidistant rows. This allows each tree the best possible change of optimal growth.
Domain is the most inclusive of the three, genus is the least inclusive
An example of a population in which evolution could take place in a relatively short period of time could be pathogenic bacteria exposed to antibiotics.
Answer: Option A
<u>Explanation:</u>
Evolution if takes place within a short period of time say the next generation that is called as micro evolution. This is caused when a specific organism exposed in a different environment at once modifies its genes to suit the new environment. This phenomenon can be very well seen in the pathogenic bacteria which are exposed to antibiotics.
When an antibiotic is prescribed to bacteria initially it nullifies its effect by destroying it. When continuously exposed to a certain antibiotic some bacteria dies but there are few which becomes resistant to it and survives. This on the other hand multiplies producing a generation that can’t be touched by the antibiotic.
The antigen-binding sites of an antibody molecule are formed from the molecule's variable regions which are described as so because their amino acid sequences can be different on different antibodies.
The specificity of antibodies is determined by the variable regions found at their endpoints. Antibodies are specialized proteins secreted by B-cells of the immune system. They are also called immunoglobulins. They contain four polypeptide chains that comprise two heavy chains and two light chains to form a Y-shaped molecule.
The variable regions, more specifically the hypervariable regions of an antibody, have a high ratio of different amino acids with the most common amino acids provided in one place. The variable region serves as the antigen-binding site while the constant region found below the variable region is determined to invade the antigen.
Antibodies are preserved in our body to identify the antigen the next time it encounters. They send the signals to the other body parts to reject the antigen and invade it.
To know more about variable regions of antibodies, refer to the following link:
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Diffusion is the movement of particles from a high concentration area to a low concentration area.
Things that can go through a membrane are ions (charged), small polar molecules. Big molecules can't go through the membrane due to its large size and disrupting the membrane.
Passive transport is the movement of substances acrpss the cell membrane w/o the use of energy. Active transport needs energy to move substances across a cell membrane.
