How have scientist started to study relationships between different groups of organisms?
a. by watching how the different organisms interact with each other
b. by stating how they mate
c. by using genetic analyses
d. by studying the organisms in their natural habitat

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

Why does it matter if osmosis is put into a “scab” or a “nosebleed? ” where would that leave him?

If there are 350 trout found in 200 square feet of a pond measuring 1000 square feet what is the estimated trout population of the pond? a. 1350 b. 1550 c. 1750 d. 2000