Find two coins: one nickel and one penny to avoid confusion. the nickel and penny will represent the parents. the head and tail of each coin will represent a single allele (so each parent has two alleles). with these coins, conduct the following trials:

test 1: aa x aa (heads and tails of each coin are a)

test 2: aa x aa (heads and tails of each coin are a)

test 3: aa x aa (head and tail of the nickel are a; head and tail of the penny are a)

test 4: aa x aa (head is dominant and tail is recessive on both coins)

test 5: aa x aa (head is dominant and tail is recessive on the nickel; head and tail on the penny are recessive).

flip each coin 20 times for each test and record the results.

determine the f1  frequencies and ratios based on the results.

the answer is d. chordata

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."    

the correct answer to this question is #5