Water moves downstream because of a gradient in which of the following?
a. pressure
b. elevation
c. saturation
d. concentration

What are antigens and antibodies? how are they involved in the body’s response to incompatible blood?

Animals that have thick fur and ae able to store large amounts of body fat live where ?

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.