Answer:
PAIRS OF SUBSTITUTES
tea - coffee
butter - margarine
petroleum - natural gas
PAIRS OF COMPLEMENTARY GOODS
printer - ink cartridge
pen-refill
Explanation:
Substitutes are goods that can replace other goods. On the other hand, complementary goods go hand in hand with one another. This implies that while substitutes can be used in isolation, complementary goods cannot be used in isolation of each other. For example, if one needs a pen, they also require a refill.
