Answer:
B. what happens when iron rusts in the presence of water
Explanation:
Chemistry is a branch of science involving the composition and changes of matter. In other words, a chemist, who is a trained specialist in the science of chemistry, seeks to answer questions related to properties of matter.
In this question, a chemist is most likely to study "what happens when iron rusts in the presence of water" because it involves a change in the chemical properties of a substance (iron) i.e. a chemical change. However, what happens when ice melts to liquid water is a physical change.
The genus is a lower classification level that lies below family and above species . Species is the fundamental category of closely related organisms that lies below the genus .
Positional energy is the energy stored within an object due to the objects position arrangement or state positional in energy is one of the two main forms energy along with kinetic energy
Answer: There are 
molecules present in 6.71 moles of 
.
Explanation:
Given: Moles of = 6.71 mol
According to the mole concept, 1 mole of every substance contains 
molecules.
Therefore, molecules present in 6.71 moles are calculated as follows.
Thus, we can conclude that there are molecules present in 6.71 moles of .
Assuming you meant cation and not action, gallium would most likely form a cation because it is a group A element
