The atmosphere is divided into four layers, the mesosphere, troposphere, thermosphere, and stratosphere. Each layer has unique physical properties. Which of the following claims about the stratosphere is true? Weather happens in the stratosphere.

There are no winds in the stratosphere.

The stratosphere is below the troposphere.

The stratosphere is warmer at the top than at the bottom.

What is a gene ? a) a section of a protein that codes for dna. b) the alternate version of a trait. c) the visible trait in the f1 generation. d) a section of dna that codes for a specific trait .

How do you know that the plant cells in these two images have different jobs, or functions? a. because all plant cells serve different functions b. because they are two different colors c. because their dna are different d. because their structures are different

Which of the following best describes the purpose of the parathyroid hormone? a. it decreases the blood calcium level and decreases blood phosphorus level. b. it decreases the blood calcium level and increases the blood phosphorus level. c. it increases the blood calcium level and increases blood phosphorus level. d. it increases the blood calcium level and decreases blood phosphorus level.