A scientist uses materials in her lab to separate DNA fragments by size. What process is she using?

A. Polymerase chain reaction (PCR)

B. Gel electrophoresis

C. Use of restriction enzymes

D. Karyotyping

Plz will mark! the diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

Which best explains how a heat pump can heat a room? cold air from the house is moved through pipes, where it absorbs thermal energy. warm air from outside is pushed into the house to replace the cold air. combustion warms the air when chemical energy is transferred to thermal energy. fuel is used to move a piston, which pushes warm air into the house.

Hector is back from his morning run and is feeling light-headed because his energy is depleted which food item will provide him with a quick source of carbohydrates