Help please thank you

Sheila conducts an investigation to see how the amount of salt dissolved in water affects the density of the water whichstatement best describes the correct plan for her procedure? the density and the amount of water are controls, and the amount of salt and the type of salt are variablesthe amount of water and the amount of salt are controls, and the type of salt and the density are variablesthe type of salt and the amount of water are controls, and the amount of salt and the density are variablesthe type of salt and the density of water are controls, and the amount of salt and the amount of water are variableso

Mi hermano espera que el tren a tiempo. a. llegas b. llega c. llegue d. llegues

Question 2 multiple choice worth 2 points) which of the following means "she has just arrived at school"?