Roberto wants to measure the lengths of the sides of a metal cube. Which tool should he use? ✔ Ruler

To make a solution, Sian must measure 15.0 mL water. Which tool should she use?

✔ graduated cylinder

An experimental procedure calls for 35.9 g sodium chloride and 15.2 g silver nitrate. What tool should be used to measure these substances?

✔ electronic balance

Mark needs to determine how much the temperature of a solution changes during a chemical reaction. Which tool does he need?

✔ thermometer

Bisphenol a (often called bpa) is a chemical found in products that people use every day, from water bottles to food containers to children's toys. unfortunately, bpa leaches out of its many products and makes its way into our bodies. what are the health effects of bpa exposure? ongoing research is finding that elevated exposure to bpa can affect a wide variety of developmental and physiological processes, but one of the first studies of bpa's health effects came about because of a simple mistake in the lab. at a laboratory at case western reserve university in 1998, geneticist patricia hunt was making a routine check of her female lab mice. as she extracted and examined developing eggs from the ovaries, she began to wonder what had gone wrong. she noticed that many of the eggs showed problems with their chromosomes, and some had irregular amounts of genetic material, which can lead to miscarriages and birth defects in mammals. she learned that a lab assistant had mistakenly washed the plastic mouse cages and water bottles with a harsh soap, releasing bpa from the plastic. knowing that bpa is an endocrine disruptor, a chemical that can enter organisms and mimic hormones, hunt set out to discover whether it had adversely affected her mice.

Apaleontologist finds a plant fossil that shows that the plant had seeds. what can the paleontologist conclude?

Contrast how pollination is different among gymnosperms and angiosperms.