Which of the following can be used to measure absolute time? select all that apply.
varv...
Chemistry, 16.12.2019 18:31, jacquelinegonz
Which of the following can be used to measure absolute time? select all that apply.
varves
tree rings
law of superposition
ratio of c-12 to c-14 in a bone sample
which statements are true? select all that apply.
an atom is the smallest complete part of an element.
an element is a pure substance made of one kind of atom.
the nucleus is the tiny center of an atom, and it contains protons and neutrons.
isotopes are atoms of the same element that contain the same number of neutrons but different numbers of protons.
the time required for one-half of the atoms from a sample of a radioactive substance to decay is called its
half-life
beta decay
alpha decay
isotope number
which statements about radiocarbon dating are true? select all that apply.
it's useful for dating all inorganic things.
it's useful for dating some organic (once-living) things.
it's useful for dating some materials that are millions of years old.
it's useful for dating some materials that are thousands of years old.
for a living organism, which of the following are true? select all that apply.
the ratio of c-14 to c-12 remains constant.
the ratio of c-14 to c-12 increases over time.
the ratio of c-14 to c-12 decreases over time.
the amount of c-14 is less than the amount of c-12.
potassium-40 (k-40) decays into argon-40 (ar-40). after 1.25 billion years, 20 grams of k-40 would be reduced to 10 grams. how much of the original k-40 would remain after 5 billion years?
0 grams
1.25 grams
2.5 grams
5 grams
uranium-238 (u-238) decays into lead-206 (pb-206). which of the following are true statements? select all that apply.
u-238 is the parent, and pb-206 is the daughter.
u-238 is the daughter, and pb-206 is the parent.
a rock sample containing a relatively small amount pb-206 is old.
a rock sample containing a relatively small amount of pb-206 is young.
if a sample is thought to be several million years old, which method would best to determine its absolute age?
c-14/c-12
ar-40/k-40
pb-206/u-238
a fossil bone is tested, and no c-14 is found. what can be said about the fossil's age?
it is 5,730 years old.
it is less than 5,730 years old.
it is more than 5,730 years old.
absolute-age dating techniques can be used to determine the age of which of these? select all that apply.
earth
some rocks
some fossils
substances made entirely of pb-206
substances made entirely of ar-40
Answers: 1
Chemistry, 22.06.2019 20:00, rafaelasoareschagas7
The picture represents the process that produces most of the energy used by living organisms on earth. which process is represented in the picture? a) the magnetic attraction between two hydrogen nuclei. b) the fusion of hydrogen nuclei to produce a helium nucleus in the core of the sun. c) the fission of hydrogen nuclei to produce a helium nucleus in the core of the sun. d) the chemical reaction between hydrogen nuclei to produce a helium nucleus in earth's atmosphere.
Answers: 3
Chemistry, 22.06.2019 22:30, skinniestoflegends
Consider a culture medium on which only gram-positive organisms such as staphylococcus aureus colonies can grow due to an elevated nacl level. a yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the ph as a result and changing the color of a ph indicator chemical. this type of medium would be referred to as a differential and enrichment culture.
Answers: 2
Chemistry, 23.06.2019 07:30, 22emilyl530
Chris is about to do an experiment to measure the density of water at several temperatures. his teacher has him prepare and sign a safety contract before beginning the experiment. which term is mostlikely part of the safety contract
Answers: 3
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