A piece of iron is heated till it becomes red-hot. It then becomes soft and is beaten to a desired shape. What kind of changes are observed in this process – reversible or irreversible ?

We the people of the united states, in order to form a more perfect union, establish justice, insure domestic tranquility, provide for the common defence, promote the general welfare, and secure the blessings of liberty to ourselves and our posterity, do ordain and establish this constitution for the united states of america. according to the preamble which action represents an appropriate role for government

By what percent will the product of two numbers change, if the first number increases by 70%, while the second number decreases by 40%.

The authors use the word “backbone” in lines 3 and 39 to indicate that