The development of bipedalism – this allowed humans to stand upright and freed our hands for tool use and other activities.2. The expansion of our brain size – this gave us the ability to think abstractly and solve problems.3. The development of language – this allowed us to communicate our thoughts and ideas to others.4. The development of culture – this allowed us to share our knowledge and traditions with others.5. The development of technology – this allowed us to create and use tools to make our lives easier.