Answer:
The air pollution in china decreases due to less usage of transportation and shutdown of industries.
Explanation:
From December to march, transportation and industrial work is greatly affected due to the corona virus. Due to reduction of activities in both transportation and industries, there is a lot of decrease occurs in the air pollution. We know that smoke produce by vehicles and industries are the main cause of pollution so that's why air pollution decreases between December to march..
Answer:
oxygen
Explanation:
A limiting factor is any condition whose decrease, increase, absence or presence is able to limit/stop population growth. Examples of limiting factors include abiotic conditions (e.g., temperature, water, oxygen, CO2, etc) or biotic conditions (e.g., food, mate, etc). There are many aquatic species that require high levels of oxygen (e.g., fish), thus being it a limiting factor for these species.
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.
