Who was the scientist who first proposed that all single-celled organisms should be put into their own kingdom?

anton van leeuwenhoek

charles darwin

carolus linnaeus

ernst haeckel

What's the waste product of electrons and pyruvate combining in fermentation?  

Which statement correctly describes other ways in which nebulae and stars are different? a. a star always has a higher density than a nebula. b. stars can form inside a nebula but a nebula can never be produced by any star. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star. reset submit

Approximately what wavelength of light is best absorbed by chlorophyll a