I believe that the answer is b
<span>When plants moved on the land they had to adapt to new environment and </span>to deal with new <span>problems. The main problem for plants was to figure out how to regulate water loss within the cells. One of the solution was the formation of the waxy covering on top of leaves-cuticle, which evolved on the surface of leaves to reduce water loss. Another problem for plants was to figure out how to obtain resources from soil and air, so they developed vascular tissue to transport water/sugar within the plant.</span>
The digital signal can then be recorded, edited, and modifies using digital audio tools. A transducer which converts sound pressure waves into electrical signals. a digital-to-analog converter will convert a digital signal back into an analog signal, which analog circuits amplify and send to a loudspeaker.
