pyrimidine

"Professor Davies is a learned scholar, renowned for her deep knowledge of ancient history. "

"The building of the bridge will be completed in a couple of weeks."

"It is very important to give your daughter independence in her life so she learns from experience."

"In RNA, uracil replaces thymine and pairs with adenine to form part of the genetic code. "

"The teacher assigned students to different positions in the classroom. "

"a block of ice"

"In the DNA sequence, cytosine always pairs with guanine, like two puzzle pieces fitting together. "

"By now, you must surely know which is which."

"My son is taking biology classes at school, learning about different types of plants and animals. "

"The air we breathe is mostly nitrogen. "

"The air we breathe is made of tiny atoms like oxygen and nitrogen. "

"During biology class, we learned that thymine is a chemical component of DNA. "