I recall that Professor Kwang had observed amoebas that had cannibalized bacteria cells. The bacteria were slaughtering the amoebas, but somehow some survived. This particular group of amoebas contained bacteria that thrived inside it. Hence the name, endosymbiosis. However, this lucky group and it's offspring could not survive without bacteria.
Answer:
For example, cells in the interior of the body may be signaled by genes to become either muscle or connective tissues, while other cells on the exterior of the body will be signaled to become epithelial cells.
Explanation:
The role of 3tc in inhibiting hiv reproduction is to interfere with enzyme trancriptase since it has a similar shape to the c nucleotide of DNA.Reverse trancriptase pick up 3tc molecule which led to termination of DNa further thus block reproduction of HIV.