A crystal contains a radioactive isotope that has a half-life of 20,000 years. You analyze a sample and find that one-eighth of the isotope remains (12.5%). How old is the sample? How many half-lives have passed?

Why is polymerase important to dna

Which region would likely have the greatest amount of biodiversity? A. a grassland region with one ecosystem, which supports very large populations of a few different species B.

What are proteins made out of? Where are they located in a cell?

Which of the following elements is NOT a common agent of chemical weathering? C H O or Ca

The bottom area of a pond or lake where very little sunlight reaches is the O trophic zone O plankton zone littoral zone O benthic zone

How many atoms is in this formula? 2C12H6O6

Explain the reason that many organisms found in the oceanic zone are unique and cannot be found anywhere else. Be sure to include two ways organisms have adapted to live in this zone

A species of fish is introduced into a lake the fish is better at hunting for food than the old fish. the old fish die off, the new fish population increases. which is the best way to describe these fish in the new ecosystem

Some populations of bats live in areas with high levels of noise pollution, such as near heavily trafficked bridges. How might the hunting behavior of bats be affected by such an environment?

Which best describes the relationship between blood flow and lymph flow? A. Blood flows through the contraction of skeletal muscle, and lymph flows through the contraction of cardiac muscle. B.