Questions: Autoimmune disorders can be the result of ineffective or defective cytotoxic T cells, neutrophils, basophils, regulatory T cells

The answer is the last one: regulatory T cells.

Explanation for each option:

1. Cytotoxic T cells: These cells are primarily responsible for killing infected or cancerous cells. While they play a role in the immune response, their dysfunction is not typically the direct cause of autoimmune disorders.

2. Neutrophils: These are a type of white blood cell important for fighting bacterial infections. They are not directly involved in the regulation of immune responses that prevent autoimmunity.

3. Basophils: These cells are involved in allergic reactions and inflammation. They do not play a significant role in preventing autoimmune disorders.

4. Regulatory T cells: These cells are crucial for maintaining immune tolerance and preventing autoimmune responses. They help suppress the immune system and prevent it from attacking the body's own tissues. Dysfunction or deficiency in regulatory T cells can lead to autoimmune disorders.

In summary, autoimmune disorders can result from ineffective or defective regulatory T cells, as these cells are essential for maintaining immune system balance and preventing self-reactivity.