Cuál es la diferencia entre las bases nitrogenadas clasificadas como purinas y las que lo hacen como primidinas? X favor gracias

What happened to rosalind franklin in 1956?

During the winter, this species of fox has white fur, but in the summer, it has brown fur. what environmental change may have lead to this fox's fur color? snow cover increase in sun's brightness volcanic eruption global warming

Anurse is caring for a 42-year-old client who is scheduled for an amniocentesis during the fifteenth week of gestation because of concerns regarding down syndrome. what other fetal problem does an examination of the amniotic fluid reveal at this time?