1. In what ways can we (humans) impact the Earth's systems?
A. Humans can negatively impact the environment by building several buildings and roads in a short amount of time.
B. humans can positively impact the environment by using alternative sources of energy and conserving energy.
C. both A and B
D. none of the above

I'm pretty sure it's b and if it's not be then it must be d hope this helps

economic impact of malaria is estimated to cost africa $12 billion every year. this figure factors in costs of health care, absenteeism, days lost in education, decreased productivity due to brain damage from cerebral malaria, and loss of investment and tourism.

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times