Nitrogen fixation a) is the process where nitrogen is converted to a usable form
b) is accomplished by plants when they break down soil.
c) occurs as a result of photosynthesis
d) none of the above

A. is the process where nitrogen is converted to a usable form

Explanation:

Fixation converts nitrogen in the atmosphere into forms that plants can absorb through their root systems. A small amount of nitrogen can be fixed when lightning provides the energy needed for N2 to react with oxygen, producing nitrogen oxide, NO, and nitrogen dioxide, NO2

"a scientist studying a whale and its surroundings would need to understand the structure of atoms in case something was negatively affecting the whale or its surroundings."

explanation:

this was from the link provided:

advantage of using stem cells in medical research:

1.       it provides medical benefits in the fields of therapeutic cloning and regenerative medicine.

2. it provides great potential for discovering treatments and cures to a variety of diseases including parkinson disease, spinal cord injuries, diabetes, alzheimer’s disease and many more.

3. limbs and organ could be grown in lab from stem cells and then used in transplant or treat illness.