Answer:
Skeletal system
Explanation:
the bones of the skeleton protect the internal organs and reduce the risk of injury on impact. For example, the cranium protects the brain, the ribs offer protection to the heart and lungs, the vertebrae protect the spinal cord and the pelvis offers protection to the sensitive reproductive organs.
Answer:
Air pressure is caused by the weight of the air molecules above
Explanation:
Air pressure is caused by the weight of the air molecules above. Even tiny air molecules have some weight, and the huge numbers of air molecules that make up the layers of our atmosphere collectively have a great deal of weight, which presses down on whatever is below.
Answer:
a. enclosing their DNA in a nucleus.
Explanation:
Prokaryotes in general have no membrane bound organelles. The cells are enclosed in a plasma membrane though .