The endosymbiotic theory to explain the origin of which structures?
a)mitochondria
b)ribosomes
c)nuclei
d)cell membranes

The endosymbiotic theory explains that mitochondria and chloroplasts descended from the same type of bacteria. Symbiosis is an interaction between two organisms of different species, and endosymbiosis is a type of symbiosis in which one organism lives inside the other one. According to the endosymbiotic theory, a host cell ingested symbiotic bacteria, which specialised into mitochondria or chloroplasts. The evidence for this theory is that mitochondria and chloroplasts, like bacteria, have their own circular DNA. and They also have their own transcriptional and translational machinery.

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.