Final answer:
According to the given options, the sentences are best combined as 'That ancient land was located in the Middle East, a hot and sunny part of the world.', effectively describing both the location and the climate concisely.
Step-by-step explanation:
The most effective way to combine sentences 2 and 3 would be the following: 'That ancient land was located in the Middle East, a hot and sunny part of the world.' This option succinctly incorporates the locational context of the ancient land within the Middle East while describing the climate of the region without using superfluous conjunctions or interrupting the flow of the sentence.