The moth species Biston betularia has two color morphs, or variants. One has a speckled white and black color, while the other i
s all black. In the early 1800s in England, the distribution was 10,000 speckled morphs to 1 black morph. That distribution changed dramatically between 1900 and 1950. By 1950, the distribution of the speckled morph had declined to less than 3% of the population and the black morph distribution increased to 97%. Which statement most likely explains this change? A. A predator of the moth underwent steep decline, which reduced selective pressures on the moth.
B. A chance mutation occurred in one black individual, which gave an advantage to the black morph's ability to survive.
C. The changes are due to normal random fluctuations that might be observed in any population over time.
D. Changes in the environment changed each morph's ability to evade predation in different ways.
D. Changes in the environment changed each morph's ability to evade predation in different ways.
Explanation:
The moth species<em> Biston betularia</em> has two color morphs, or variants. One has a speckled white and black color, while the other is all black. Over the period of time, the distribution of moths dramatically changed between 1900 and 1950 in such a way that black morph became dominant but speckled morphs became very much declined in abundance. The reasons behind this change was heavy industrial pollution in UK between 1900 and 1950.
When the environment became very polluted, dark and blackish, the speckled moth had more chanced of getting eaten by predators thats why they declined in number as compared to black morphs. On the other hand, backgrounds of grime and soot made black morphs less visible to the predators and they survived well. This is an excellent example of natural selection that only those specie better survive that have the ability to cope better with adverse environmental fluctuations.
This is because elements are pure substances with only one atom. When two or more elements are combined, you get compound elements; which allows for more substances to be created.
Broad-spectrum antibiotics can cause antibiotic resistance.
Explanation:
Antibiotics are the substances that inhibit the growth of or kill the bacteria and hence, these are used as medications for the treatment of a lot of bacterial diseases.
These antibiotics can either be of broad-spectrum or the narrow spectrum.
The broad-spectrum antibiotics are the ones that are effective against a variety of bacteria, both gram-positive and negative whereas the narrow-spectrum antibiotics are the ones that target only a specific type of bacteria.
Since the bacteria can mutate very fast and hence, develop antibiotic resistance, the doctors usually avoid prescribing broad-spectrum antibiotics and only use them when the causal bacteria is completely unknown.
Hence, in the given case the provider prescribes separate medications for both types of bacteria.
Meningocele (MM) is known as meningeal cyst and it is the protrusion
of the membrane that cover the part of spinal cord through the defect in the
vertebral column. Thus, Meningocele (MM) is the least
common fom of spinal bifida and spina bifida is the bony defect in the
vertebral column through the meningeal membrane.
