The sentence that has a verb in the active voice is B. Guglielmo Marconi perfected a type of radio technology.
The rest of the sentences have their verbs in the passive voice. If you wanted to make a passive sentence out of B, you would say - A type of radio technology was perfected by Gugliermo Marconi.
<span>Because the moth tears its way out of the cocoon, thus destroying the silk thread. Silk farmers want the thread from a cocoon to be in a single piece and not in many smaller and, sometimes, unusable pieces.</span>
I watched a video on this before
