Cells that are a structured material.
Answer: High flow O2 is best. It is used with those persons who present with severe cluster headache or migraine; the triptan is contraindicated by her B.P., Ibuprofen would not be very useful with presentation of aura and bilateral nature of her headache; ergotamine is surely contraindicated given her history.
Explanation:
This complexity of cell processes is attributed to the fact that D. Eukaryotes have specialized membrane bound organelles, in all of their specialized cells, to position or separate biochemical processes to certain environments within the cell.
Of course we can survive without clothes. We evolved a hairless body because our ancestor was an ape that was forced to live in the hot, open savanna, where fur is not needed. In fact, many people around the world did not wear any clothes. Native Hawaiians, for example, wore no clothes when the first European explorers arrived. Amazonians and Africans also did not wear clothes. Humans evolved in Africa about 150,000 years ago, and the early humans wore no clothes. Humans started migrating out of Africa about 60,000 to 70,000 years ago. They followed the coast line and went all the way to Australia. These early migrants ended up in places that required no clothes. Only when humans migrated to places like ice age Europe and northern parts of Asia (northern parts of China, Japan and Korea) did they need to wear clothes or animal skins to stay warm. Wearing clothes blocks out the sun and these people were in danger of vitamin D deficiency, which leads to rickets. Rickets can result in muscle cramps, broken or deformed bones and even death. In order to absorb enough UV light to synthesize vitamin D, there was strong selection pressure to evolve lighter skin tones.
The habit of wearing clothes, even in places that do not require them, was spread by European Christians. Basically they forced and/or shamed the natives to wear clothes wherever they went.Of course, not wearing clothes means that humans will no longer be able to live in temperate areas around the world, at least not during the fall and winter months.
Answer:
A gene mutation can be described as errors in the nucleotide sequence of a gene due to errors in the DNA replication process or due to any mutagen. On the other hand, a chromosomal mutation can be described as a change in the structure of a DNA or changes in the number of chromosomes.
A gene mutation occurs in a single gene whereas a chromosomal mutation will affect many genes. Hence, gene mutations will be comparatively less lethal than chromosomal mutations.
Example of gene mutation: Sickle cell anemia
Example of chromosomal mutation: Down's Syndrome
