Complex sentence: In 1972, the Sperm Whale was listed as an Endangered Species and the following year, the US Congress amended the Endangered Species Act, outlawing the killing of whales and the use of their oil.
Split into simpler sentences: In 1972, the Sperm Whale was listed as an Endangered Species. The following year, the US Congress amended the Endangered Species Act, outlawing the killing of whales and the use of their oil.