Step 1: Definition of National Political Party
According to the Election Commission of India (ECI), a political party is recognized as a national party if it fulfills certain criteria such as securing a minimum percentage of votes and recognition in at least four states.
Step 2: List of national political parties in India (as per recent classification)
1. Bharatiya Janata Party (BJP)
2. Indian National Congress (INC)
3. Communist Party of India (CPI)
4. Communist Party of India (Marxist) (CPI-M)
5. Bahujan Samaj Party (BSP)
6. Nationalist Congress Party (NCP)
7. All India Trinamool Congress (AITC)
Step 3: Conclusion
Therefore, there are a total of seven national political parties in India.
\[
\boxed{7 \ \text{National Parties}}
\]
The following table shows the ages of the patients admitted in a hospital during a year. Find the mode and the median of these data.
\[\begin{array}{|c|c|c|c|c|c|c|} \hline Age (in years) & 5-15 & 15-25 & 25-35 & 35-45 & 45-55 & 55-65 \\ \hline \text{Number of patients} & \text{6} & \text{11} & \text{21} & \text{23} & \text{14} & \text{5} \\ \hline \end{array}\]