If the verb in the independent clause is in the present tense, the tense that the verb in the indirect quotation should be is <span>remain in its original tense.
</span>You don't have to shift tenses because it is present in the independent one.
For example:
He says: "I need to wash my hair."
He says that he needs to wash his hair.
You wouldn't say - he says that he needed to wash his hair.
Density and Convection<span> at the Beach. </span>Convection<span> is heat transfer due to a density differential within a </span>fluid<span>. ... The </span>current<span> begins when the air over the hot sand is heated and begins to </span>rise<span> because of its lowered density. Air from above the ocean is colder and more dense.</span>
B. The First Amendment protects the students' right to wear the armbands; they weren't disruptive, and the school allowed others to wear controversial symbols.