why does earth have a more complicated global circulation than a simple one-cell model (where air rises at the equator and sinks at the poles)?

Which of the following are the functions of the skeletal system? blood cell production in soft marrow tissues and mineral reserves largest organ of the body for defense and support vitamin d production and pumping blood through vessels voluntary movement and contractile movement

Which topic is most likely to be studied by bo which topic is most likely to be studied by botanist? insect metamorphosis, viral infection, plant growth, animal physiology

I've created a synthetic cellular membrane that is made up of phospholipids, but contains no proteins. which of the types of movements across a membrane would not function with my synthetic membrane?