Is Remy hair 100% human hair?

Could you please clarify whether Remy hair is composed of 100% human hair? I'm particularly interested in understanding the authenticity and quality of this type of hair, as I'm considering purchasing it for a wig or hair extension. It's important for me to know if it's genuinely human hair, as this would greatly influence my decision. Additionally, could you elaborate on the manufacturing process involved in creating Remy hair? Is there a specific technique used that preserves the natural texture and appearance of human hair? Thank you for your assistance in clarifying this matter.