Signal word or phrase: because
2. The glaciers began to melt; therefore, the land bridge between Asia and North America became flooded.
Cause : The glaciers began to melt
Effect : the land bridge between Asia and north America became flooded.
Signal word or phrase: therefore
3. Because they wanted to learn about different civilizations that existed, archaeologists studied artifacts.
Cause : they wanted to learn about different civilizations that existed
Effect : archaeologists studied artifacts
Signal word or phrase: because
4. Early man slowly started to grow food, and as a result, their lives became easier.