The number of electrons in the outermost shell of an atom determines its reactivity.
<span>The correct answer is The cell is eukaryotic because it has chloroplasts. Prokaryotic cells don't have chloroplasts as they are only found in eukaryotic cells. The closest thing there is to chloroplasts are the cyanobacteria who function similarly and also photosynthesize but are in the end not chloroplasts themselves.</span>
Flu vaccines need to be revised and changed every year because the flu virus constantly mutates. Flu viruses can change in two ways: drift or shift. Antigenic drift occurs when genes of the virus slowly change during replication until the immune system no longer recognizes it. On the other hand, antigenic shift occurs when a major change in the virus happens. This usually leads to a totally different kind of virus. This is what happened during the H1N1 scare in 2009.
DNA viruses like mumps are less prone to mutation due to the presence of DNA polymerase. RNA viruses are more prone to mutation because they undergo reverse transcription to simulate the role of DNA.
True. This is because in the lab they can determine the bacteria that may be causing the UTI.
The invention of the microscope allowed the first view of cells. English physicist and microscopist Robert Hooke (1635–1702) first described cells in 1665. He made thin slices of cork and likened the boxy partitions he observed to the cells (small rooms) in a monastery.
