Answer:
Because the vaccine is an antigen from living, weakened or killed microorganisms that activate the immune system and the body produces protective antibodies.
Plant cells have what is perhaps the most complex outer coverings. Plant cell walls are made largely of cellulose which forms strong, highly rigid, almost indigestible coverings that protect the cell and gives it shape.
The change in weather pattern caused forest to become sparse and hot weather caused the reduction of apes as they had less food and difficulty in surviving the climate.
Explanation:
In Miocene epoch volcanic mountain chains were created in Central Africa which abruptly changed the local weather.
The sea-level got drop due to global cooling of that time.
This resulted in continental drift making land connection of Africa with Eurasia.
The primates started migrating through this route.
The African forest become dry causing selective pressures in primates.
The cooler climate in Eurasia caused extinction and migration of primates to Africa in late Miocene epoch.
The hot and humid climate and less woodland caused a reduction in number of apes which were replaced by modern world monkeys.
