White blood cells have an important function in the human immune system. they leave the blood stream and attack and engulf invading bacteria and fungi. how do white blood cells move when outside of the blood stream

The energy of blowing wind can be harnessed to create electricity. why is wind considered a renewable energy source? a) wind does not cause destruction of the environment. b) wind turns the blades of a windmill that creates electricity. c) wind provides only a very small amount of electricity to the united states. d) wind comes from atmospheric conditions that are available indefinitely.

According to theories of how life began, how did early organic molecules begin to separate from the outside world? a: specialized enzymes were required b: chains of amino acids created a barrier c: formation of microspheres or vesicles d: rna catalyzed the formation of membranes

Which of the following observation darwin shape his concept of descent with modification? a) species diversity declines farther from the equator. b) fewer species live on islands than on the nearest continents. c) birds live on islands located farther from the mainland than the bird's maximum nonstop flight distance. d) south american temperate plants are more similar to the tropical plants of south america than to the temperate plants of europe. e) earthquakes reshape life by causing mass extinctions.