1. which of the following is true about the fossil record?
a. it shows the earth's climate has been constant throughout history.
b. it shows that all species found on earth today are identical to all their ancestors.
c. it is used to show that the youngest fossils will usually be discovered in the deepest layers of rock.
d. it provides clues about how organisms have changed over time.

The correct answer will be option D- It provides clues about how organisms have changed over time.

Explanation:

Fossils are the remnants of plants and animals which were present millions of years ago. Fossils are formed due to the deposition of sand, silt, clay and mud over the dead and decayed parts of plants and animals inside a water body.

Since fossils are the present form of the past organisms, they are used by the evolutionary biologists as evidence to study the history of life on Earth related to their evolution and relationship with the existing species.

Thus, option D is the correct options.

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation:

weathering is the answer.