Why do birth control pills contain estrogen?

a. eggs are made of estrogen.
b. women normally have no estrogen in their bodies.
c. sperm use progesterone to fertilize eggs.
d. estrogen controls the ovulation process.

Which of the following will not cause mass extinction? a. drastic change is weather b. geological change c. both a and b d. none of the above

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

Researchers want to use edna to look for an invasive species in the water which of the steps would be likely do last