Que documentos se emplean para acreditar la identidad?

Does anyone know what my spanish teacher means by this? i need to use plural forms of the verb ser. and she asked me to use a couple of adjectives to describe the boys collectively and then the girls collectively?

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

What two types of verb is venir? regular and stem-changing transitive and stem-changing irregular and stem-changing irregular and compound