The flu vaccine is a medicinal shot which is supposed to prevent/ and or decrease your chances of getting the flu. It is supposedly working as stated by the producers of this vaccine however many children have been given this vaccine and it dosen`t work. The recommendations are appropriate as it is better to be safe than sorry. However there are some negative effects. For example a person would get a cold afterwards and this of course is sickness. Overall, I recommend not highly, but as i stated earlier it is better to be safe than sorry.
Answer:
A major obstacle life would have to overcome is having only a limited amount of natural light and then the rest of the time is darkness.
When an object reflects all light, you will see white light.
