What is double and helical about the double helix?

In molecular biology, the term double helix refers to the structure formed by double-stranded molecules of nucleic acids such as DNA. The double helical structure of a nucleic acid complex arises as a consequence of its secondary structure, and is a fundamental component in determining its tertiary structure. 

meiosis is the first to occur after the nuclei of opposite of opposite mating types fuse

answeranovulation;