[问答题]
(a) Compare the energy needed fz fxx0rrd )t7ex 3x9;jor thzzes x4 7t,m. *qo/gfoe first reaction of the carbon cycle to that for a dox 7m4 zq*, zof.gse/teuterium-tritium reaction.
(b) If a deuterium–tritium reaction requires $T \approx 3 \times 10^8\ \text{K}$, estimate the temperature needed for the first carbon-cycle reaction.
