In the 1950s, when watson and crick were working on their model of dna, which concepts were well accepted by the scientific community?
a. chromosomes are made up of protein and nucleic acid.
b. chromosomes are found in the nucleus.
c. genes are made of dna.
d. genes are located on chromosomes.

Option (1), (2) and (3).

Explanation:

DNA is the genetic material of all the living organisms present on earth. The DNA contains the nitrogenous bases, pentose sugar and the phosphate group. DNA strands runs in the opposite direction and shows polarity.  

Watson and Crick explain the structure of DNA based on the X ray diffraction produced by Rosalind. According to the structure, chromosomes are present in the nucleus and contains the DNA and wrapped around the proteins. The genes is considered as the functional segment of DNA.

Thus, the correct answer is option (1), (2) and (3).

b. the carbon cycle ensures living things have a source of hydrogen

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds