Hey I know it's a lot who ever answer all I'm going to give brainliest answer thxs 1) DNA is a microscopic molecule made up of only chemicals. 2) In the all that was known about life was what could be seen through a . 3) Chromosomes are made of and . 4) The ingredients that make DNA are known by the letters . 5) The first pictures of DNA were taken using crystallography. 6) To determine the structure of DNA, Watson & Crick chose to build . 7) Watson & Crick announced they had a DNA model on . 8) After seeing the model, Rosalind Franklin said that it was . 9) Chargaff’s rule stated that the amount of and the amount of were equal and the amount of and the amount of were equal. 10) The X-pattern of DNA was the result of a shape known as a . 11) In a molecule of DNA there could be hundreds of millions of . 12) The letter always combines with and the letter always combines with . 13) Watson & Crick produced their final model on . 14) Rosalind Franklin never received a Nobel prize because she . 15) For DNA to be replicated it must first be . 16) The single strand of DNA is then and formed into a .

1) nitrogen bases

2) the 1950’s; microscope  

3) DNA and protein

4) nucleotides

5) X-ray diffraction

6)  ball-and-stick model-building

7) 25 April 1953

8) was critical to Watson and Crick

9) adenine-timine; guanine-citosine

10) double helix

11) base pairs  

12) G with C and A with T

13) 1953

14) died

15) unwound

16) synthesized; a new molecule

Explanation:

Nitrogenous bases are used to construct nucleotides. Until the discovery of the helical shape of the DNA molecule, were only possible to identify the genetic material (chromosomes) by the microscope. Chromosomes are composed of DNA and proteins (histones). Nucleotides are the building blocks of the DNA molecule. The X-ray diffraction data obtained by Rosalind Franklin were used to decipher the DNA structure. The ball-and-stick is a molecular model where atoms are represented by spheres and bonds are represented by rods. Chargaff's rules indicate that the content of cytosine is equal to guanine and adenine is equal to thymine. Rosalind Franklin died of ovarian cancer in 1958.  The double-stranded DNA molecule must be unwound and then the DNA strands serve as templates to synthesize identical DNA molecules.