In one experiment lederberg used gal and gal– strains of e. coli. one half of a plate that contained medium with galactose as the only carbon source was inoculated with phages that came from lysed cells of the gal strain. the other half of the plate was left uninoculated. a gal- strain was then placed on the entire plate. numerous colonies appeared on the half of the plate inoculated with the phage, whereas only a few appeared on the half that was not inoculated with phage. explain what happened using appropriate terminology.

This is an example of adaptation due to a progressive mutation

Explanation:

At the beginning, the bacteria can use the galactose as carbon source for it needs, but since this food is getting out in every new generation. The new generations can be adapted to survive with smaller quantities of galactose until there will be one generation that can survive with any galactose source, when this offspring reach the area of the plate without galactose, then it can be grown in ant area.

a. possible errors

d. new questions

explanation:

predictions and planning happen before. a summery comes after. errors you get after investigation and new questions propose what you can look for in the future.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation: