Which of the following describes a properly controlled experiment?

If bacteria are much too small to see, what is one reason why can we see colonies in the petri dishes that have plenty of food to eat after only a few days?

Match with o for organic and i for inorganic for each compound

The ruiz family is exchanging euros for us dollars. the exchange rate is 1 euro equals 1.35261 usd. since the ruiz family knows that usd are stated to the nearest hundredth of a dollar, they used the conversion ratio