I think the one that is most needed for cosmologist to study the age of the universe is : D. distance travelled It is used to determine the Hubble constant today and extrapolating back in time with the observed value of density parameters
Answer: Mass– the amount of matter than an object is made of. Mass does not change with gravity. Weight– the amount of gravity acting on (pulling down on) an object (or mass). Gravity– a natural force that pulls objects downward.