Which of the following is an example of an element: A) H₃O
B) He
C) Ca₂CO₃
D) CaCl₂
PLEASE ANSWER QUICKLY

One does not belong why? ice, gold ,wood ,diamond and table salt

Word equation for k+ h2o yield koh + h2

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)