The concept of _____________ states that living things could arise from nonliving things.

The period of time it takes for one-half of a radioactive isotope to decay is called its _____________.

The age of Earth is estimated to be approximately _____________.

Spallanzani demonstrated that _____________ would not grow in flasks that contained broth and had been boiled and sealed.

The surface of Earth is protected from damaging ultraviolet light by _____________.

The age of fossils, such as those of bones, can sometimes be determined by _____________.

The _____________ neck of Pasteur’s flasks prevented microorganisms from getting into the broth in the flasks.

The half-life of carbon-14 is 5,730 years. One-fourth of an initial amount of this substance would remain after _____________ years.

Scientists have inferred that the first cells were _____________.

Spontaneous generation has been offered as an explanation for _____________.

If the half-life of a radioactive isotope is 5,000 years, how much of the radioactive isotope in a specimen will be left after 10,000 years?

Isotopes are forms of the same element that differ in _____________.

How did Redi test the hypothesis of spontaneous generation?

What did Pasteur do in his experiments on spontaneous generation that other scientists before him had not done?

The half-life of carbon-14 is 5,730 years. How much of an initial amount of this substance would remain after 17,190 years, which is three times its half-life?