Which step you should take before performing a scientific investigation A. print the directions after you complete the experiment

B. test out all of your emergency equipment you may need

C. clarify any confusing information in the instructions

D. Purchase the equipment and chemicals you will need

all of these

Explanation:

these are all good things u should do

D. Purchase the equipment and chemicals you will need

Explanation:

14 days is the half-life of phosphorus-32

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.