What instrument was essential to the development of the cell theory ( i need a verified answer)

Which of the following lines of evidence would best support your assertion that a particular plant is an angiosperm? a) it produces seeds. b) it retains its fertilized egg within its archaegonium. c) it lacks gametangia. d) it undergoes alternation of generations.

The influenza virus cause the flu, but not other diseases. why?

Genetic disorders can result when sister chromatids fail to seperate properly. during what phase is this problem most likely to occur?