Answer:
The function of the pleura is to allow optimal expansion and contraction of the lungs during breathing. The pleural fluid acts as a lubricant, allowing the parietal and visceral pleura to glide over each other friction free. This fluid is produced by the pleural layers themselves.
Answer:
The correct option is <em>B) ultraviolet region, especially below a wavelength of 320 nm.</em>
Explanation:
Ultraviolet light carries an enormous amount of energy in it. It is invisible to the human eye. When UV light with enormous energy and wavelength lesser than 320nm, hits the DNA, it causes changes in the structure of the DNA. Mostly, it affects the thymine nitrogenous base regions and forms pyrimidine dimers. The structure of the DNA changes on all the sites where dimers form and hence, they cannot be properly transcribed.
Answer:
I could be wrong but I believe it is,
"rocks," and "dark matter"
Answer:
The correct answer is ''carbon dioxide, water vapor and nitrogen.''
Explanation:
About 4.5 billion years ago, Earth was a very geologically active planet. So many volcanic fumes formed the primitive atmosphere, which was mostly made up of water vapor, carbon dioxide, sulfur, and nitrogen. At this point, oxygen was barely present and the oceans did not yet exist. The primitive atmosphere is the one before the Precambrian, it was reductive, that is, it lacked free oxygen, and only had ammonia, methane and hydrogen, the high temperature of the atmosphere in its early stages facilitated the reaction of these gases to form organic compounds from which life may have emerged. UV rays passed, because ozone did not exist.
