Alexander Fleming discovered the penicillin in 1928. He noticed that some bacteria he had left in a petri dish had been killed by naturally occurring penicillium mould.The penicillin began the era of antibiotics, has been recognized as one of the greatest advances in therapeutic medicine. The research required to determine if the penicillium extract was safe and killed bacteria was done at Oxford University.P<span>rogram of animal experiments and clinical trials was carried.</span>
Answer:
As air pressure decreases oxygen continues to account for about 21% of the gasses in the air as it does at sea level. But, there is less oxygen because there is less of all of the air's gasses
Answer and Explanation:
The father had 54% of the body covered by burns, since a little more than half of his body was burned. In addition, to calculate the percentage of body burn, the following values are considered: head, arms and legs - 9% torso front - 18% torso back - 18%. In addition, the father feels little pain in his legs (which had worse burns) because the third degree burn destroys the nerve endings, while the second degree burn only damages these endings promoting intense pain.
The daughter had 9% of her body burned by first degree burns, which corresponds to her lower limbs. These burns involve the skin and the epidermis, for this reason, we can say that the legs are the part of the daughter's body that has compromised hair and epidermis.
In many regions, wetlands have been filled in so as to be able to use the land for farming. Wetlands are vital for reducing the intensity of floods, as they tend to hold back some of the water. Without wetlands, flood will tend to wash increased sediment and pollutants into the ocean, which can have a detrimental effect on marine life. Coastal developments can also have a negative effect on marine life. The removal or moving of beach sand is in particular damaging to intertidal organisms that depend on specific coastal environments, and rocky shores can be smothered by sand, whereas sand environments can change into bare rocky environments. Impounding of rivers and reduced river flow can result in estuaries becoming closed. Many marine organisms, such as fish, depend on estuaries as nursery areas where they lay their eggs. Reduced opening of estuaries means that many fish species cannot reproduce. Built harbours result in changed currents and alteration of the sea floor, which also disrupts marine ecosystems.
