Frank is doing an experiment to find out how the amount of oxygen dissolved in water affects the growth of algae in a body of water. he dissolves different amounts of oxygen in ten otherwise identical samples of water.

what should frank do next?
place each sample of water in a freezer, and measure the temperature at which each freezes.

add a pair of minnows to each sample of water, and measure the rate at which they reproduce.

carefully bring each sample of water to a boil, and measure the temperature at which each boils.

add equal amounts of algae to each sample of water, and measure the rates at which they grow.

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

An ecologist studied the same species of deer during the summer and the winter. she noticed that during the summer, when there was plenty of food, the deer were energetic and playful. however, during winter when food was scarce, the deer moved more slowly and did not run unless they needed to escape a predator. which scientific fact is best supported by her observations?

2polnis which of the following is an advantage of an in vitro experiment?me