PLEASE HELP! What type of reaction is the following?

3fe+4h2o=fe3o4+4h2

A. Synthesis
B. Decomposition
C. Single Replacement/Single Displacement reaction
D. Double Replacement/Double Displacement reaction

According to newtons universal law of gravitation, which would change the parh of the ball so it traces out widest curved path possible?

Which lists the organs in the correct order as food passes from the mouth to anus?

This is important 1. what happens to the speed of molecules in water vapor when it condenses to form a liquid? (2 points) the molecules slow down. the molecules speed up. the molecules slow down and then speed up. the molecules speed up and then slow down. 2. how might human activities change to compensate for a decrease in water supplies? (2 points) humans might build a factory. humans might build drainage systems. humans might extract more water from the ground. human behavior does not change because of the water cycle. i'll be grateful if anyone can answer these 2 questions !