2 Na(NO3) + Ca(CO3) à Na2(CO3) + Ca(NO3)2

i think it is true since you can test the answer and can use observations to complete it.

i think that the answer is c

warm front forms when a moist, warm air mass slides up and over a cold air mass. as the warm air mass rises, it condenses into a broad area of clouds. a warm front brings gentle rain or light snow, followed by warmer, milder weather.

hope i !