<span>Recruitment of motor units.
Altering frequency of the stimulation.</span>
Answer:
Carbon dioxide is added to the atmosphere naturally when organisms respire or decompose (decay), carbonate rocks are weathered, forest fires occur, and volcanoes erupt. Carbon dioxide is also added to the atmosphere through human activities, such as the burning of fossil fuels and forests and the production of cement
<span>D) they lack DNA so they must use the DNA of the host cell
Viruses do in fact have their own DNA.</span>
Can you elaborate ?????????????????????????