Well in my words, The vaccine is the weakened or dead version of the virus(pathogen). This actually prepares the body to be un-affected if it ever comes in contact with the virus (pathogen) again. After the vaccine is injected your body produces memory cells. These help your body become immune to the same virus (pathogen) twice. So basically it helps protect your body from dangerous viruses or pathogens, and develops immunities against them.
I really hope this helped :D
Temperature and density share an inverse relationship. As temperature increases, the space between water molecules increases—also known as density, which therefore decreases. If the temperature of water decreases its density increases, but only to a point. At a temperature of 4°C pure water reaches its maximum or peak density, cooled further it expands and becomes less dense than the surrounding water which is why when water freezes at 0°C it floats.
Salinity and density share a positive relationship. As density increases, the amount of salts in the water—also known as salinity, increases. Various events can contribute to change in the density of seawater.
Salinity can decrease from the melting of polar ice or increase from the freezing of polar ice. Evaporation increases salinity and density while the addition of freshwater decreases salinity and density.
It is how the world changed so from the beginning of time to right now.
