Gastrointestinal surgical operation is a treatment for diseases of the parts of the body involved in digestion. This consists of the oesophagus (ee-sof-uh-gus), stomach, small intestine, large intestine, and rectum. It also includes the liver, gallbladder, and pancreas.
 Surgery may be used to remove a cancerous or noncancerous growth or damaged part of the body, such as the intestine. It may also be used to repair a problem like a hernia (a hole or a weak point in the wall of the abdomen). Minor surgical techniques are used to display and diagnose problems of the digestive system. 
Below are gastrointestinal conditions that can be treated with surgery: 

• Appendicitis. When the appendix becomes infected and inflamed, it may be removed (appendectomy).
• Colon cancer and other gastrointestinal cancers. Surgery is done to remove cancerous tumours in the digestive system and parts of the digestive system that have cancer. For example, a surgeon may remove a tumour as well as part of the pancreas, liver, or intestine with cancer.
• Diverticular disorder.

Ph.D. or Doctor of Philosophy is a doctorate degree that is offered by almost 868 universities in India. In general, the duration of this course is 3 years and a student must complete it within a time span of maximum of five years. There are more than 257 Ph.D. courses available in India. 
The primary eligibility criteria for Ph.D. is to have a master’s degree or an MPhil with a minimum qualification of 55% marks. There’s a 5% relaxation for all the candidates who belong to SC/ST/OBCs and differently-abled categories. Although, the eligibility can also change as per the university requirement. The Ph.D. Admission 2021 is primarily based on the entrance examination carried out by various universities. Students appearing for Ph.D. Admission 2021 must have a minimum qualification of 50% marks in their postgraduate degree and should qualify the entrance examination. Those who are seeking admission to the Ph.D. course will get it primarily based on the merit lists released by the universities. 
Ph.D. admission is acquired on the basis of merit of UGC NET/CSIR UGC NET or if you want to pursue PhD in Engineering and Technology, then a GATE rating. Ph.D. is a doctorate degree diploma that may be pursued in plenty of specializations that fall under Engineering, Management, Commerce, Arts, Humanities, and so on. Students get a number of Ph.D. Jobs once they complete their Ph.D. Course. Few Ph.D. schools in India additionally offer Ph.D. with stipends to deserving applicants. The average yearly package after Ph.D. is INR 6,00,000 to INR 9,00,000. Before 2017, Doctorate of Philosophy turned towards pursuing a distance schooling mode, however now as consistent with UGC, the distance gained knowledge has been revoked and it can only be pursued most effectively in full-time or part-time mode. One can pursue Ph.D. from IGNOU with INR 7,000 yearly fee within a period of five years. 

Eligibility:

In order to pursue Ph.D., one must meet the noted eligibility standards: 
For General Candidates:- Minimum of 55% marks in Post Graduation 
For SC/ST/OBC/Differently abled applicants:- Minimum of 50% marks in Post Graduation Candidates with earlier experience in the field of study or an organization to emerge as strongly eligible for the course.