Step 1: Evaluate each statement individually.
Statement I: Flagellates exhibit gliding locomotion with the help of their flagellae
This is incorrect. Gliding locomotion is typically observed in organisms like sporozoans, not flagellates. Flagellates use their flagella for locomotion but do not exhibit gliding movement.
Statement II: Multiple fission in \textit{Amoeba} is called sporulation
This is correct. Sporulation is a process of asexual reproduction where multiple daughter cells are formed inside a cyst during unfavorable conditions.
Statement III: Syngamy in \textit{Plasmodium} is hologamy type
This is incorrect. Hologamy refers to a condition where whole organisms act as gametes. In \textit{Plasmodium}, syngamy involves distinct gametes — it is not hologamy.
Statement IV: Fusion of pronuclei of gametes is called amphimixis
This is correct. Amphimixis is the process of true sexual reproduction involving the fusion of male and female pronuclei.
Conclusion: The correct statements are (2) II, IV.