What is the name given to the twisted step ladder form of DNA?

If assuming tasting ptc as a simple gene trait,what other genotype would you select to put in this missing genotype box that could result in this phenotype

Explain how the political influence of african americans leaders became weaker.

The rapid decomposition of organic matter produces evidence which supports: the slow accumulation of coal deposits long ages of the earth rapid burial of vast amounts of vegetation biblical account of noah's flood