Double helical model of DNA was proposed by _______.

🔑Key Points:
Watson and Crick
American biologist James Watson and English physicist Francis Crick discovered DNA in the 1950s.
The double helix structure of DNA was first discovered by James Watson and Francis Crick, using experimental data collected by Rosalind Franklin and Maurice Wilkins.
They determined that the structure of DNA is a double-helix polymer, the molecule containing human genes.
 
🔴Additional Information:Robert Hook
Cell is known to be the fundamental, structural and functional unit in all life forms, including plants, animals, bacteria, and human.
The smallest unit of life, the cell, is often referred to as the "building block" of life.
The cell was discovered in 1665 by English Botanist Robert Hooke, one of the first scientists to use a light microscope.  
Robert Brown
Robert Brown, a British Biologist discovered the nucleus in the year 1831.
This cell organelle was named nucleus according to the Latin word nucleus/ nucleus meaning a seed.
The study of the nucleus is called Karyology.
The nucleus is a double membrane-bound dense protoplasmic body, which controls all the cellular metabolism and encloses the genetic information of the cell.
The nucleus is considered the controller or director of the cell.