The correct statements regarding carbon nanotubes (CNTs) are 1, 3, and 4 because they highlight the potential applications of CNTs in nanomedicine and biotechnology. CNTs can serve as efficient carriers for drugs and antigens due to their high surface area and biocompatibility (Statement 1). They are also utilized in biochemical sensors for detecting biomolecules, benefiting from their electrical conductivity and functionalization possibilities (Statement 3). Statement 4 is correct as certain types of CNTs can exhibit biodegradability under specific conditions, which is essential for reducing environmental impact and ensuring safety in medical applications. However, the claim about them being made into artificial blood capillaries (Statement 2) has limitations, as current research primarily focuses on other materials for vascular grafts, making this statement less established in the field.