How do you say to fail (a class) in spanish? reprobar or aprobar

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

Decide if the following definite article and noun agreement is correct or incorrect. el calendario correct incorrect

Explain stem changing -ir verbs and how they're different to stem changing -ar and -er verbs in the present subjunctivepoints!