If the atomic number of an element is 6 and its mass number is 13, how many neutrons are
contained in the nucleus?
19
8
7
6

Four types of motile cells in human body?

Which type of neuroglia is found outside of the brain?

Ricardo notices that when he plays soccer in the rain, his ball does not seem to go as far after a kick. what is the best scientific question that ricardo could ask about this observation? is soccer better played in the rain or sun? how does rain affect the distance a soccer ball can travel? how does rain affect the speed of a soccer ball? is soccer affected by the rain?