which situation describes a correlation that is not a causal relationship? (1) car color and number of car accidents(2) hours spent studying and test score(3) amount of exercise each week and the time it takes to run a mile(4) distance to reach a destination and the amount of gasoline used

The amount of money, in dollars, in an account after t years is given by a = 1000(1.03)^t. the initial deposit into the account was $_^a0 and the interest rate was _a1% per year. only enter numbers in the boxes. do not include any commas or decimal points^t. the initial deposit into the account was $__^a0 and the interest rate is % per year.

Mexico city, mexico, is the world's second largest metropolis and is also one of its fastest-growing cities with a projected growth rate of 3.2% per year. its population in 1991 was 20,899,000 people. use the formula p = 20.899e0.032t to predict its population p in millions with t equal to the number of years after 1991. what is the predicted population to the nearest thousand of mexico city for the year 2010?

What is the number 321,000,000 in scientific notation? also what is the number? ?