How do i solve this? and show out the working

Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b. slope c. benchmark d. index contour

Why is it possible for different microorganisms to extract energy not only from carbohydrates and other biological molecules but from a large variety of substances?

Movement that is like a t a type of wave that transfers energy where the particles in the medium move in a circle motion while the energy travels left or right. a type of wave that transfers energy where the particles in the medium move perpendicular to the direction in which the energy is traveling. transfers energy from one location to another a type of wave that transfers energy where the particles in the medium move parallel to the direction in which the energy is traveling. movement that is back and forth, like an equal sign = 1. wave 2. parallel movement 3. perpendicular movement 4. transverse wave 5. longitudinal wave 6. surface wave