Answer:
the element oxygen , represented by the symbol o, is classified as a pure substance
My Answer: The death rate begins to fall, but birth rates remain high for a time.
Why?: Many of our countries are in Stage 2, that is why the government is concerned about our overpopulation.
Hope I helped! :D
Answer:
hemotrophs are organisms that obtain energy by the oxidation of electron donors in their environment. Chemoautotrophs use inorganic energy sources to synthesize organic compounds from carbon dioxide. Chemoheterotrophs are unable to utilize carbon dioxide to form their own organic compounds.
Explanation:
Answer:
Phoebus Levene( 1896, Sagor Russia - Septemeber 1940, New York)
Explanation:
These were developed by Phoebus Aaron Theodor Levene ,he was a russian who studied medicine, with keen interest in organic chemistry.
He migrated to the US in 1891, and started practising medicine in 1892.Due to his strong interest in research he combined research(1894) in molecular structure of sugars with medical practice,But this was cut short when he contracted tuberculosis.
Between 1896- 1906,he collaborated with many nucleic acids and protein exoperts e.g Albrecht Kossel and Emil Fischer to wok on the structure of DNA.And headed the Rockefeller Institute for Medical Research.
He works included :the isolation of Nucleotide-monomers of DNA
:the isolation of D-ribose sugar from ribonucleic acid molecule.(RNA)
Discovery of 2-deoxyribonucleic ,
How the components of Nucleotide(phosphate group,sugars, and organic bases) combined to form nucleotide, and how the latter undergo condensation reaction to form DNA.
