Answer:
The Sierra Madre
Step-by-step explanation:
The Sierra Madre is the longest mountain range in the Philippines. Spanning over 540 kilometers (340 mi), it runs from the province of Cagayan down to the province of Quezon, forming a north–south direction on the eastern portion of Luzon, the largest island of the archipelago. It is bordered by the Pacific Ocean to the east, Cagayan Valley to the northwest, Central Luzon to the midwest, and Calabarzon to the southwest. Some communities east of the mountain range, along the coast, are less developed and so remote that they could only be accessed by taking a plane or a boat.
