<span>One of the essential early steps in the inventing process is creating a prototype--which, simply defined, is a three-dimensional version of your vision. Creating a prototype can also be one of the most fun and rewarding steps you'll take. That's because developing a prototype gives you the opportunity to really tap into your creativity, using those skills that inspired your invention idea in the first place. And whether you're making your prototype at home or hiring the services of an engineer, seamstress or machinist, it's truly exciting to see your idea transformed into something tangible and real.</span>
the (drug and control) are the variable that you will change throught the conducted investigation.
Answer:
The Mid-Atlantic Ridge runs down the center of the Atlantic Ocean. ... The rift valley is 1 to 3 km deep, about the depth and width of the Grand Canyon. In contrast, the East Pacific Rise spreads fast at rates of 6 to 16 cm per year (more than 20 cm per year in the past).
Im pretty sure the answer is d but not 100% sure
