destroy asset is not permitted to avoid data loss?

using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI;

public class Reset : MonoBehaviour {

 public static bool reset = false;

 public Transform[] startingLocation;
 public GameObject[] whatToSpawnPrefab;
 public List<GameObject> whatToSpawnClone = new List<GameObject>();

 public GameObject Player;

 public Rigidbody2D P1;

 public Text Sc;

 public void RestartButtonClicked()

 {
     // reset
     reset = true;

     //reset score
     ScoreManager.Score = 0;

     //reset player
     P1.velocity = Vector2.zero;
     P1.angularVelocity = 0;
     Player.transform.position = new Vector3 (0f, 0.4f, 0);
     Player.transform.eulerAngles = Vector3.zero;

     //reset stars
     if (whatToSpawnClone.Count > 0)
     {
         for (int i = 0; i < whatToSpawnClone.Count; i++)
         {
             if (whatToSpawnClone[i] != null)
             {
                 Destroy(whatToSpawnClone[i]);
             }
         }
     }
     whatToSpawnClone.Clear();
     SpawnObject(0, 0, Quaternion.Euler(0.505f,0.417f,0));
     SpawnObject(1, 1, Quaternion.Euler(-0.497f,0.417f,0));
     SpawnObject(2, 2, Quaternion.Euler(0.007f,0.815f,0));
     SpawnObject(3, 3, Quaternion.Euler(0.007f,0.017f,0));

     reset = false;
 }

 void SpawnObject (int prefabIndex, int locationIndex, Quaternion quaternion) 
 {
     if (prefabIndex < whatToSpawnPrefab.Length)
     {
         if (locationIndex < startingLocation.Length)
         {
             whatToSpawnClone.Add(Instantiate(whatToSpawnPrefab[prefabIndex], startingLocation[locationIndex].transform.position, quaternion) as GameObject);
         }
         else
         {
             Debug.LogError("Starting location index ( " + locationIndex + " ) need to be less than " + startingLocation.Length);
         }
     }
     else
     {
         Debug.LogError("Spawn prefab index ( " + prefabIndex + " ) need to be less than " + whatToSpawnPrefab.Length);
     }
 }

 // Update is called once per frame
 void Update () 
 {

 }

}