<p>the (most studied) form of curiosity (is called) interest type curiosity, (it is the )motivation to learn about something (because) it is entertaining or novel.</p>
<p>And </p>
<p>Finding ways (to produce) electricity (both) cheaply and cleanly (are among) the (most pressing) challenges facing the modern world</p>
<ol>
<li><p>(it is the) is wrong because it is a comma splice. it should be “which is the”</p></li>
<li><p>(are among) because the “are” is mistakenly matched with “finding” which is singular. it should be “is among”</p></li>
</ol>
<p>So whats wrong with it</p>
<p>You’re separating two independent clauses with nothing except a comma, which is a comma splice and thus bad grammar. “It” should be replaced with “which”</p>