Given a scientific passage and an answer, generate a question for the given answer.

Passage: The strength of bases is measured on a scale called the pH scale, which ranges from 0 to 14. On this scale, a pH value of 7 indicates a neutral solution, and a pH value greater than 7 indicates a basic solution. The higher the pH value is, the stronger the base. The strongest bases, such as drain cleaner, have a pH value close to 14. Answer: ph scale
The strength of bases is measured on what scale?

Passage: Most plants continue to grow as long as they live. They grow through a combination of cell growth and cell division (mitosis). The key to plant growth is meristem, a type of plant tissue consisting of undifferentiated cells that can continue to divide and differentiate. Meristem allows plant stems and roots to grow longer (primary growth) and wider (secondary growth). Answer: meristem
What is a type of plant tissue consisting of undifferentiated cells that can continue to divide and differentiate?

Passage: Animals such as bats and dolphins send out ultrasound waves and use their echoes, or reflected waves, to identify the locations of objects they cannot see. This is called echolocation. Animals use echolocation to find prey and avoid running into objects in the dark. You can see in the Figure below and also at the following URL how a bat uses echolocation to find insect prey. http://www. bsos. umd. edu/psyc/batlab/headaimmovies/nsf_challenge/nsf4. wmv. Answer: echolocation
What is the term for the method of sending out ultrasound waves to determine the locations of objects?