Answer: Even though you have not included the complete question, and the format of your question is confusing, it is possible to understand that you have been asked to complete the gaps with the appropriate possessive pronoun in Spanish.
These are the correct answers:
1. Alejandro, ¿es TUYA?
2. No, no es MÍA.
3. Pero estos guantes sí son MÍOS.
4. No es TUYO y tú lo sabes.
5. ¡No es VUESTRO!
6. ¡No son SUYAS!
7. Los calcetines son SUYOS.
Explanation: Just to elaborate a little on the answer, it can be added that in this exercise they are asking you to complete fill out the blank with the appropriate possessive pronoun (mine, yours, theirs, and so on). Much like in English, they are used in Spanish in order to avoid repeating information that has already been given and is clear. So, for instance, instead of saying "But these gloves are <em>my gloves</em>," Alejandro says "But these gloves are <em>mine</em>." "Mine" (<em>míos</em> with an accent) replaces "my gloves."