The answer is disruptive selection. The allelic frequency of the population shifts to the extreme traits that are being favoured by natural selection as opposed to the intermediate traits. The variance in the population increases and two species begin to emerge. Directional selection, on the other, favours one end of the extreme traits. Disruptive selection is a form of sympatric speciation.
A directional selection is the tendency for an extreme phenotype such as large size or extreme coloration to be favored over other phenotypes. Direct selection allows the favored or selected allele to increase as a result of differences in survival and reproduction among different phenotypes.
Answer:The answer is D) They produce microtubules that attach themselves to the chromosomes and aid in separating them.
Surface tension is the property of the surface of a liquid which allows it to resist an external force. It is due to the cohesive nature (stickiness and clumpability) of the water molecules. Since water has a strong surface tension:
1) The surface tension of water provides the necessary wall tension for the formation of bubbles with water
2) It is responsible for the shape of liquid droplets, too
3) Small objects will "float" on the surface of a fluid, as long as the object cannot break through and separate the top layer of water molecules
If surface tension is weak, the reverse happens. Bubbles will come from round to spherical, small objects will not float, water will fall as it is, without forming spherical droplets and will not immediately spread.
The indigestible carbohydrates that are found in plant cell walls are called dietary fibers. Dietary fibers are group of complex carbohydrates that is found mostly in vegetables, fruits and legumes. They include beans, whole grains such as wheat, nuts etc. Dietary fibers cannot be digested in mammals because the body lacks digestive enzyme that is required to break them down.
The correct answer is - cleaning ballast water.
In the great lakes, 65% of the invasive species come from the ships that carry ballast water tanks to stabilize them on the long route journeys, this release invasive species when loading and unloading cargo.
Cleaning up these ballast water is one of the most effective ways to stop the new invasive to enter the Great Lakes.