Why are plants usally the first organisms to spread to a new area

Which of the following parabolas opens down?

Luisa sells stuffed animals. she sells her stuffed elephant for $34.90, and the sales tax is 6% of the sale price. about how much is the sales tax on the elephant?

Acertain drug is made from only two ingredients: compound a and compound b. there are 3 millimeters of compound a used for every 4 millimeters of compound b. if a chemist wants to make 693 milliliters of the drug, how many milliliters of compound a are needed?