Why don't the Prefabs in my GameObject appear?

Hello, everyone. I am still learning how to use Unity. I am trying to create a Randomizer that randomly spawns a group of Peaches. I noticed that when I place the Prefabs for the Peaches in the Spawner, the Randomizer works; however, when I place the GameObjects that contain the Prefabs for the Peaches in the Spawner, the Randomizer does not work. Could someone provide a solution to the issue then explain what was causing the issue? Thank you.

The Code that I am using:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PeachSpawner : MonoBehaviour
{
public List spawnObjects = new List();

public float timeToSpawn; 

private float currentTimeToSpawn;

public bool isTimer;

public bool isRandomized; 

// Start is called before the first frame update
void Start()
{
    currentTimeToSpawn = timeToSpawn; 
}

// Update is called once per frame
void Update()
{
    if (isTimer)
    {
        updateTimer();
    }
} 

private void updateTimer()
{
    if (currentTimeToSpawn > 0)
    {
        currentTimeToSpawn -= Time.deltaTime; 
    }

    else
    {
        SpawnObject();
        currentTimeToSpawn = timeToSpawn;
    }
}

public void SpawnObject()
{
    int index = isRandomized ? Random.Range(0, spawnObjects.Count) : 0; 
    if (spawnObjects.Count > 0)
    {
        Instantiate(spawnObjects[index], transform.position, Quaternion.identity); 
    } 
}

}

Can you elaborate a bit on ‘does not work’? Do you get any errors?