With reference to 'stem cells', frequently in the news, which of the following statements is/are correct? 1. Stem cells can be derived from mammals only. 2. Stem cells can be used for screening new drugs, 3. Stem cells can be used for medical therapies. Select the correct answer using the codes given below:

1. Statement 1 is incorrect. Stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. While stem cells from mammals (like human embryonic stem cells or adult stem cells) are widely studied, stem cells also exist in other multicellular organisms, including plants and non-mammalian animals. 2. Statement 2 is correct. Stem cells, especially induced pluripotent stem cells (iPSCs) generated from patients, can be differentiated into specific cell types (e.g., liver cells, heart cells, neurons). These differentiated cells can then be used in vitro to screen the toxicity and efficacy of new drugs, providing a potentially more accurate model than animal testing for predicting human responses. 3. Statement 3 is correct. Stem cells hold great promise for medical therapies, often referred to as regenerative medicine. The goal is to repair or replace damaged tissues or organs. Established therapies include bone marrow transplants (using hematopoietic stem cells). Research is ongoing for using stem cells to treat conditions like heart disease, diabetes, Parkinson's disease, and spinal cord injuries.