<span>the plates located at our planet's surface move because of the extreme heat in the earth's core that then leads to the molten rock in the mantle layer to move. it moves in a pattern called a convection cell, it forms when warm material rises, cools down, and eventually sinks down. </span>
Answer:
b hummingbirds have the ability to hover while drinking nectar
Explanation:
because this allows for power in both the upward and downward beats of the hummingbirds wings
The answer is D, white blood cells.
The main function of white blood cells is to defense the body from bacteria or other pathogens. There's 2 main kinds of white blood cells, lymphocytes and phagocytes. Lymphocytes mainly produce antibodies that can kill bacteria or any pathogens, and phagocytes can ingest the pathogens directly.
Therefore, since the white blood cells can protect our body, they're part of our immune system.
The answer is A, friction.
Friction is the force that resists movement, and that's why oil is used as a lubricant and why ball bearings are used for machines that need to move with very little friction(i.e. bike wheels, roller skates, fidget spinners)
Answer B is too vague
C will probably reduce efficiency greatly, but not specifically in a way that turns work into thermal energy.
D is the same as C, except that it places the blame on the person using the machine, not the machine itself.
Hope I helped clear it up for you :)
