Final answer:
The claim that a surface low-pressure system needs high pressure aloft to strengthen is false. Low-pressure systems intensify with divergence aloft, which can occur in both low and high-pressure areas.
Step-by-step explanation:
The statement that a surface low-pressure system will not strengthen unless there is high pressure aloft is false. Low-pressure systems typically intensify or build when there is a divergence of air aloft, which can occur in areas of low pressure as well as high pressure. This divergence aloft effectively sucks air up from the low-pressure center at the surface, causing the low pressure to deepen or strengthen as more air is rising and less air is replacing it from above. Conversely, high pressure aloft could actually inhibit the rising motion of air and make it more difficult for a low-pressure system to develop further.