Answer:
No
Explanation:
Electromagnetic waves travel slowest in dense matter such as solids. On the other hand, mechanical waves travel quickly through solids. For example, sound travels fastest through solids. This difference is because EM waves do not rely on the movement of particles to travel. Since they require no medium they can travel the fastest in space or other vacuums.
I think the correct answer from the choices listed above is option A. For metamorphism to occur, the parent rock must be in solid form. Metamorphism is the alteration of the structure of a rock by factors like heat and temperature so it must be the material should be in solid form.
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.
Answer:
1.It produces silk which is a high quality fibre
2.to destroy the gelatinious substance inside cocoon so as to obtain silk thread
3.To avoid it from hatching
4.they carry pollen grains while roaming plant to plant and help in cross pollination