Which are characteristics of scientific questions? Check all that apply. asking about subjective matters
having a wide focus on many topics
addressing a gap in knowledge
possibly leading to a testable hypothesis
already having fully confirmed explanationsWhy aren't descriptive investigations repeatable?

asking about subjective matters

possibly leading to a testable hypothesis

addressing a gap in knowledge

I got soo confused about that last part. I didn't know if that was an option or something you needed to be answered.

Descriptive investigations are not repeatable because they are based only on observations made at a single point in time. The results may vary at a different time. In addition, descriptive investigations do not contain variables that may indicate cause-and-effect relationships.

a boiling water reactor does not boil the water. a pressurized water reactor boils the water faster. a pressurized water reactor is heated directly by the core. a pressurized water reactor does not use fission.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.