If you cut a tree trunk into pieces, the resulting pieces and dust add up to the same mass as the original trunk. This is a demonstration of

The law of conservation of mass

Explanation:

The Law of Conservation of Mass dates from Antoine Lavoisier's 1789 discovery that mass is neither created nor destroyed in chemical reactions. In other words, the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction.

answer; i believe its (ovulation);

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.