Write in short about the structure of the heart?

the heart is divided into four chambers consisting of two atria and two ventricles; the atria receive blood, while the ventricles pump blood. the right atrium receives blood from the superior and inferior vena cava's and the coronary sinus; blood then moves to the right ventricle where it is pumped to the lungs.

sulfur dioxide

explanation: acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.