Which process in living things produces oxygen that enters the oxygen cycle?

Sarah is sitting at the top of the slide in the schools playground. which will increase sarah’s kinetic energy a- an additional child is added to the top of the slide. b- sarah is pushed and moves down the slide. c- sarah climbs down the ladder and off the slide. d- the ladder is moved to the other side of the yard.

If you have a difficult time knowing where your hand is without looking at it you may be having a problem with your what ?

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?