What makes mitochondrial DNA useful as a molecular clock? - It is only found in select organisms, making it easier to compare relationships between species that have it.

- A large portion of the DNA ring is not vital to structure or function, allowing it to accumulate neutral mutations.

- Its rate of mutation increases over time as organisms continue to evolve and differentiate from each other.

- A slow mutation rate makes it useful for determining evolutionary relationships between ancient species.

After reading the paragraph below, answer the questions that follow. researchers have created a robot that has a very thin leg that is moved by cardiac (heart) cells contracting in unison. the robot, made of a polymer similar to that used in making contact lenses, is bathed in heart cells with supporting cells, which then attach to the robot and provide movement as they contract. all of the cardiac cells working together can cause the robot leg to move in a way that individual cells could not. this is an example of a. emergent properties of cells. b. energy flow through an ecosystem. c. adaptation. d. internal environment regulation.

Asample of digestive juice was removed from the stomach of a pig. the juice was placed in a test tube along with some grains of wheat. a second test tube was set up containing an equal number of wheat grains, with distilled water rather than digestive juice. the test tubes were kept for 8 hours at 40 degrees c. after 8 hours, the grains inside the digestive juice had broken into tiny particles. the grains of wheat, in the water, were wet but otherwise unchanged. what is the control group?

Which part of the microscope controls the amount of light which shines through the lens?