A scientist carried out an experiment to separate cell structures in animal cells.
The cells were broken open to release the cell structures.
This extract was filtered into a centrifuge tube and then spun in a centrifuge. The heaviest cell structure sank to the bottom forming pellet 1, as shown in the diagram.
The liquid above pellet 1 was poured into a clean centrifuge tube and spun in the centrifuge at a higher speed to separate the next heaviest cell structure. This cell structure sank to the bottom, forming pellet 2.
This procedure was repeated twice more to obtain pellet 3 and pellet 4, each containing a single type of cell structure.
Which row shows the order in which the cell structures were collected?
1 )
A
B
3 )
C
4 )
D
