Because bacteria mutates that's why we have a new flu vaccine every year , because strains of DNA in the bacteria change all the time.
The west Nile Virus is pathogen which caused the West Nile fever and encephalitis. The pathogen was introduced in 1999 in the Western Hemisphere and infected a major population in new york. It then expanded to 12 states and district of columbia. The major carrier of the pathogen was Avian and Mosquitoes species. In between 1999 to 2008, nearly 2500000 people were infected and nearly 1500 people died. Also there were thousands of cases of encephalitis or meningitis.
Fermentation is a type of chemical process which enables heterotrophs to obtain energy without oxygen . Heterotrophs uses procedure of fermentatation to cultivate because in process of fermentation enzymes are the catalysts and they provide energy to heterotrophs
In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell (mitosis) and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half to produce Haploid gametes (meiosis)
In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell.——————Neurotransmitters are endogenous chemicals that enable neurotransmission. It is a type of chemical messenger which transmits signals across a chemical synapse, such as a neuromuscular junction, from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell.