Solution: C. Increased use of surrounding land
Upward urban growth will increase pollution as the number of people will increase. The increase in population and obstruction of free movement of air because of upward urban growth will result in a "heat island". Since the number of inhabitants is going to increase with upward urban growth, waste management will also become an issue.
Examples
High respiration rates from mass global population
Deforestation
B. a form of gene is the correct answer
Human and the natural ones can change the ecosystem