<span>1. A hydrogen fuel cell is more efficient than a combustion reaction because very little of the released energy is released as HEAT.
We need more energy emit as light and less heat. Lesser the heat more the efficiency.
2. </span>when used at home a fuel-cell illuminates the need for <span>an electrical grid</span> because the cell is portable.
As said, it is portable.
Answer:
Seismographs record seismic waves. They contain a weight and a pen attached to a spring. The seismograph is bolted to the ground so during an earthquake it moves with the ground, whilst the weight and pen remain still. The pen moves across a rotating paper roll recording the seismic waves.
Hope this helped, have a good day
