When magnesium carbonate, MgCO2, reacts with nitric acid, HNO3, it forms magnesium nitrate, Mg(NO3)2, and carbonic acid, H2CO3. Carbonic acid then breaks down into water and carbon dioxide. Which two types of reactions take place in this process? A) synthesis and decomposition B) single-replacement and combustion C) double-replacement and decomposition D) double-replacement and combustion

Which traits do human embryos have that link them to a common ancestor with fish and reptiles? a. scales and tail b. gill slits and scales c. tail and gill slits d. hair and tail

The is a particle with one unit of positive charge a. proton b. positron c. electron d. nucleus awnser quick it is a important science test!

Agroup of students is studying convection current. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other is in an area with warm air. after 10 minutes, the balloon are released from a height of 1 meter. which of the following to the students most likely observe? a) the warm balloon expands and rises. the cold balloon shrinks and sinks b) the balloon both rise. the cold balloon is larger than the warm balloon c) the cold balloon expands and rises. the warm balloon shrinks and sinks d) the balloon rise at the same rate. both balloons are the same size