Sustainable development is the concept of meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. It balances economic, social, and

1.1 Sustainable development is the concept of meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. It balances economic, social, and environmental considerations. $\boxed{\text{Sustainable development is meeting present needs without compromising future generations' ability to meet their own needs.}}$

1.2 Two reasons for differences in development are:

• Historical factors, such as the legacy of colonialism or past conflicts, which can hinder economic growth and institutional stability.
• Economic factors, including unequal access to natural resources, unfavorable trade agreements, high national debt, or widespread corruption. $\boxed{\text{Historical factors and Economic factors}}$

1.3 Sustainable development integrates three core elements: economic development, social equity, and environmental stewardship. Economic development focuses on creating prosperity and livelihoods, for example, by investing in renewable energy projects that generate jobs and economic growth. Social equity ensures fair distribution of resources and opportunities, such as providing universal access to quality education and healthcare for all citizens. Environmental stewardship involves protecting natural resources and ecosystems, like implementing policies to reduce pollution, conserve biodiversity, and manage waste effectively. True sustainable development is achieved when these three pillars are balanced, ensuring that current needs are met without compromising the ability of future generations to meet their own needs.