Abiologist studying a desert ecosystem observes that the population of a lizard species increases following a particularly hot, dry period that causes a snake population to decline. what could the biologist hypothesize about the roles of these two species?
a. the lizard preys on the snake.
b. the lizard is a parasite of the snake
c. the snake and lizard use the same limiting resource.
d. the snake is a keystone species in the ecosystem

Elements and compounds are pure substances that cannot be broken down physically into a simpler substance. a physical change doesn’t break the bonds between atoms of a substance or form new ones. compounds can be broken down by a chemical change. a chemical change breaks chemical bonds and/or forms new ones between atoms of a substance. what simple substance would a compound break into? the basic elements that make it up! for example, if you passed a very strong electric current through water you’d break the chemical bonds in water and be left with oxygen and hydrogen. which of the following is an example of a chemical change? a separating water into different glasses b breaking frozen ice cubes with a hammer c running an electric current through water d boiling water to evaporate it on a stove

Where can you find prokaryotic and eukaryotic cells?

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.