We can improve the shelf life of foods by chemicals, exposing foods to oxygen, or exposing foods to carbon.) ,drying, fermentation, or freezing.) is a food preservation technique that uses bacteria.

We can improve the shelf life of foods by adding chemicals to food. Fermentation is a food preservation technique that uses bacteria.

Explanation:

100% on test.

ANSWER: 1{ Adding chemicals to food | 2{ fermentation

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.