Question

why are some energy sources considered less reliable? *
they cost more money
they are illegal to use
they depend on environmental conditions like weather
they do not produce electricity

which combination best represents the main challenges energy planners must balance?
speed, population, and geography
reliability, environmental impact, cost, and demand
weather, technology, and politics
energy storage, nuclear waste, and recycling

Explanation:

1. For the first question: Many variable renewable energy sources (e.g., solar, wind) are less reliable because their output depends on weather and environmental conditions, which are inconsistent. Cost, legality, and electricity production do not define reliability in this context.
2. For the second question: Energy planners must balance core factors: ensuring energy is reliably available, minimizing environmental harm, keeping costs manageable, and meeting consumer energy demand. The other options do not cover the primary, broad challenges of energy planning.

Answer:

1. They depend on environmental conditions like weather
2. Reliability, environmental impact, cost, and demand