When a muscle receives nerve signal contracts and pulls on a tendon.
The answer is A. Environmental conditions are not always right to produce flowers and seeds for sexual reproduction.
Most plants are able to reproduce either way because even if the conditions aren't right for the plant, it can still make more flowers so it doesn't die out.
I hope this helps! :D
<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.
One astronomical unit<span> is the approximate mean</span>distance<span> between </span>the Earth<span> and </span>sun<span>. It's about 93 million </span>miles<span> (150 million km), or 8 light-minutes.</span>
