The Dutch microbiologist van Niel who first demonstrated anoxygenic photosynthesis hypothesized that every molecule in nature can be used as a source of:
carbon or energy by some microorganism.
photosynthesis results in oxygen production.
microbes are found in mesophilic environments on Earth.
microbes cannot live deep within Earth.
photosynthesis occurs deep within Earth.

Read the following scenario to answer the following question. in some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. applying the biological species concept, the sterility of ligers reveals that a. lions are probably a subspecies of tigers b. tigers and lions are the same species c. a new species called "ligers" is forming d. tigers and lions are separate species

Is this mrna or rna need need the answer in a hurry

How do the sperm cells get from the stigma to the ovules? a. they slide down the petals to the bottom of the flower. b. they travel through pollen tubes. c. they travel along filaments. d. insects carry the sperm cells from the stigma to the ovules.