During the spread plate method of isolation, a few drops of the initial culture is transferred to tube
a. a loop of the tube a culture is then transferred to tube b and so on until tubes a through d were produced. which tube is expected to produce a higher number of cfus on the plate?

Tube A will produce a higher number of CFUs on the plate

Explanation:

This procedure is called dilution: when a loop of the previous (and more concentrated culture; tube A) is diluited in new culture medium, few microorganisms disperse in the new liquid. This results in a less concentrated culture (tube B).

When drops of this diluited culture (tube B) are spread in a plate, microorganisms can grow far from each other and iniciate an isolated colony. A lower number of colonies will grow from this tube.

Results of the spread method of isolation: with enough dilution, each colony is generated from a single microorganism. Then, all the microorganisms in a colony have grown from a single cell and they have the same genetic material (they are genetically identical)