An antimicrobial chemical was added to a population of bacteria. the initial population was 107 living cells (10,000,000). after 2 minutes, only 106 cells still remained alive. after another 2 minutes (4 minutes of total treatment), about how many cells would still be alive?

I believe after four minutes the population of the cells would be 10^5. Antimicrobial chemicals are those chemicals or agents that destroy or kill bacteria ad other pathogens. Therefore, addition of an antimicrobial chemical in a bacteria population triggers death of the cell, and since the rate of cell division is lower than the rate of death the number of cells reduces with time.According to te above information the population reduces by a factor of 10, thus if the initial population  was 10^7 after two minutes, the population was 10^6, which means after the next two minutes the population would be (10^6)/10 which gives 10^5

An autotrophic protist - they can perform photosynthesis and mainly consist of unicellular algae. they can be divided into number of systematic group according to the shape of their cell and the type of photosynthetic pigments they use.