A positively charged pith ball, K, is hung from a ring stand. You hold a glass rod in your hand; your partner rubs the glass rod with a piece of silk cloth. Next you approach the pith ball very slowly with the glass rod. The results can be seen here. State an appropriate conclusion for this investigation.

A) The positive charge from K is transferred to the glass rod.
B) The glass rod acquired a positive charge from the silk; like charges repel and K moves away.
C) The glass rod acquired a positive charge from the silk and that charge was transferred to K.
D) The glass rod acquired a negative charge from the silk; opposite charges repel and K moves away.

Legumes, a type of plant, require rhizobia, a type of soil bacteria, to survive since these organisms fix nitrogen during photosynthesis. rhizobia use the legumes for food. what would most likely happen to the legume population if rhizobia suddenly became extinct?

Which statement best describes how the nucleus, the rough endoplasmic reticulum, and ribosomes interact during protein synthesis?

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.