Potassium is a mineral which appears in abundance in all living plant and animal cells. The human body uses it to promote regular heartbeat, help build muscles, help contract muscles, regulate blood pressure, and control the water balance in body tissues and cells. Calcium is a mineral that primarily functions in your body by making your bones and teeth hard. The rest is in your blood and soft tissues; it helps your muscles contract and your blood clot, and helps your nervous system work properly. According to your knowledge of atomic structure, explain why the calcium atom is smaller than potassium atom.

Astudent from one of the research labs is having trouble preparing a slide for examination and photographing. the bacterial slide that he has brought to you was prepared using a commercially purchased stain. he has asked for your in determining what he is doing wrong so that he can change the lab protocols and continue on with his project. after examining the slide under oil immersion, you determine that no bacteria are present even though the student is able to show you the culture he used to make that slide that has visible growth in the liquid medium. which of the following statements does not explain the fact that there are no bacteria present on the student’s slide? by not allowing a glass slide to completely air dry before heat fixation, the flame will cause the surrounding water to boil and this will damage the bacterial cell. overheating during the fixation step boiled the water within the bacterial cells and resulted in the cells bursting. insufficient heating of the slide did not drive out the thin layer of water and this resulted in minimal bonding between the bacteria and the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide.