Answer and Explanation:
The Cretaceous–Paleogene extinction, which occurred around 66 million years ago, is defined as a mass extinction that wiped out around three-quarters of species on Earth.
Among the organisms that disappeared during this event, we find mammals, birds, fish, sharks, pterosaurs, birds, reptiles, insects, and some plant species.
This event is marked by the presence of a sediment layer known as the K-Ph boundary which showed important levels of iridium, an element that is abundant in craters. Therefore, after its discovery, scientists hypothesize this extinction occurred due to the impact of the giant Chicxulub crater which changed the conditions of the atmosphere.
Answer:
A) The role of bacteria fixing nitrogen is very important because it fixes atmospheric nitrogen in the roots of plants. For example, Azotobacter is a bacteria which lives in the root of the higher plants. The bacteria fixes nitrogen for the plant and the plant gives habitat and food to the bacteria and hence, both get benefit.
B) Nitrifying bacteria are the bacteria which converts ammonia into nitrates. Examples are Nitrosomonas and Nitrobacter.
C) Denitrifying bacteria is a type of bacteria which converts nitrates into atmospheric nitrogen. Examples are Serratia and Pseudomonas.
The correct answer is adding foreign DNA to a bacterial cell.
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Transformation is a process in which genetic material in the form of deoxyribonucleic acid (DNA) is transferred into the recipient bacteria. It can occur between two bacterial cells or it can be induced in laboratory procedures (making the cell permeable to foreign DNA by exposing it to special conditions).
</span><span>infecting bacteria with bacteriophages is called transduction.</span>
D. To convert sound waves into mechanical waves.
Insulin and glucagon are both enzymes that regulate the levels of sugar in the blood
