What type of codon is methinonine?

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?

When does an organism become an adult during a life cycle? a)before metamorphosis is complete b)after producing offspring c)after development is complete d)before gametes fuse

What evidence for the age of the earth is indicated by the fact that sedimentary rock is found on mountain tops? that the earth has expanded outward from water beds that mountains formed first before anything else that some force lifted the rocks from the water the earth is not very old and has not had time for many rock layers to form