span class="fl">7</span>, <span class="fl">8</span><span class="op">)</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="co">#  * choose where the ticks appear</span></span></span>
<span class="r-in"><span><span class="va">m</span> <span class="op">+</span> <span class="fu">scale_x_continuous</span><span class="op">(</span>breaks <span class="op">=</span> <span class="fl">1</span><span class="op">:</span><span class="fl">10</span><span class="op">)</span></spa