"in all areas of the world, groundwater is an important source or drinking water. however, in many areas, the groundwater is being polluted, mainly by nitrates. sometimes the groundwater is so polluted, it is no longer able to be used as drinking water. what is the most likely source of the nitrate pollutants?"

Below, the levels of organization in a multicellular organism are shown from least to most complex. which level of organization can be described as several different types of tissues working together to perform a common task?

Did you know that a single bee would have to go to over 2 million flowers to make a single pound of honey?

Why do leaves change color in the fall? green pigments break down and no longer mask the color of chlorophyll. chlorophyll breaks down and no longer masks the colors of other pigments. red- and yellow-colored pigments grow and mask green-colored chlorophyll. green-colored chlorophyll breaks down and turns red and yellow.