The half-lives of isotopes are all measured in millions of years.

a. True

b. False

Which of the following is an example of a monopole sound source? a. gunshot b. tuning fork c. all of the choices d. loudspeaker working without an enclousure

We can see that stars do not appear randomly on the plot but appear to be grouped in four main regions. Most stars seem to fall into group A.

Which statement correctly describes a sample of gas confined in a sealed container? (1) It always has a definite volume, and it takes the shape of the container. (2) It takes the shape and the volume of any container in which it is confined.

Time that is measured in definite periods such as minutes, day, and years is called

1500 millimeters to km

Which would not be associated with stable atmospheric conditions afternoon thunder showers is the answer

Which is not a characteristic of a compound? It is a mixture of elements. It has properties that differ from its component elements. It has a fixed proportion of elements.

Can you think of other possible ways scientists can determine what climate was like in the past besides studying ice cores?

Which sub-layer thins out into space, where there is no air

Complete and balance the molecular equation, including phases, for the reaction of aqueous ammonium bromide, nh4br, and aqueous lead (ii) acetate, pb (c2h3o2) 2.