How do plants get the nitrogen they need? a. through photosynthesis b. directly from the soil c. from the air d. from bacteria living in their roots

Correct D) From bacteria living in their roots

Nitrogen is an essential plant nutrients, but it is metabolically unavailable to higher plants and animals. It is available to some species of microorganism by biological nitrogen fixation in which nitrogen is converted to ammonia with the help of enzyme dinitrogenase.

The process of breaking apart the two atoms in a nitrogen molecule is called nitrogen fixation. Plant obtain the nitrogen they need from the soil which is already fixed by the bacteria and archae.

Example: Azobacter, Nostac    

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.

to figure the total magnification of an image that you are viewing through the microscope is really quite simple. to get the total magnification take the power of the objective (4x, 10x, 40x) and multiply by the power of the eyepiece, (usually 10x)