Question

select the text from the paragraph that best helps you understand that decipher means figure out. there may be more than one correct choice.
sedimentary rock forms in layers over time. when the layers form, plant and animal remains can create fossils in the rock. older rock layers are usually found deeper underground. unfortunately, movements of earths tectonic plates can cause some older layers to appear higher than younger layers. this movement makes determining the age of rocks challenging. however, geologists can use fossils to help them decipher the age of rock layers. this is why fossils are so important.

Explanation:

To understand that "decipher" means "figure out", we look for context showing determining rock layer age. The sentence "This movement makes determining the age of rocks challenging. However, geologists can use fossils to help them decipher the age of rock layers" connects "decipher" to the act of determining (figuring out) rock layer age, as the challenge of determining age is introduced, and then fossils help with deciphering (figuring out) that age. Also, the prior info about tectonic movements complicating age - determination sets up the need for geologists to figure out the age, which "decipher" here relates to.

Answer:

"This movement makes determining the age of rocks challenging. However, geologists can use fossils to help them decipher the age of rock layers."