Question: where do the signals for apoptosis come from
[{'answer': 'from other cells', 'provenance': [{'wikipedia_id': '2457', 'title': 'Apoptosis', 'start_paragraph_id': 3, 'start_character': 293, 'end_paragraph_id': 3, 'end_character': 309, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2457', 'title': 'Apoptosis', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14876348887509012114}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2457', 'title': 'Apoptosis', 'start_paragraph_id': 3, 'start_character': 18, 'end_paragraph_id': 3, 'end_character': 654, 'bleu_score': 0.871304113344555, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14876348887509012114}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '21590012', 'title': 'Cytosis', 'section': 'Section::::Etymology and pronunciation.\n', 'start_paragraph_id': 4, 'end_paragraph_id': 4, 'meta': {'evidence_span': ['Cytosis is a transport mechanism for the movement of large quantities of molecules into and out of cells. There are three main types of cytosis: endocytosis (into the cell), exocytosis (out of the cell), and transcytosis (through the cell, in and out). The word "cytosis" () uses combining forms of "cyto-" and "-osis", reflecting a cellular process. The term was coined by Novikoff in 1961. Endocytosis is when a cell absorbs a molecule, such as a protein', 'Cytosis is a transport mechanism for the movement of large quantities of molecules into and out of cells. There are three main types of cytosis: endocytosis (into the cell), exocytosis (out of the cell), and transcytosis (through the cell, in and out). The word "cytosis" () uses combining forms of "cyto-" and "-osis", reflecting a cellular process. The term was coined by Novikoff in 1961. Endocytosis is when a cell absorbs a molecule, such as a protein\rhighlight sentence(s) containing evidence, not only the answer', 'Cytosis is a transport mechanism for the movement of large quantities of molecules into and out of cells. There are three main types of cytosis: endocytosis (into the cell), exocytosis (out of the cell), and transcytosis (through the cell, in and out). The word "cytosis" () uses combining forms of "cyto-" and "-osis", reflecting a cellular process. The term was coined by Novikoff in 1961. Endocytosis is when a cell absorbs a molecule, such as a protein']}}]}, {'provenance': [{'wikipedia_id': '563093', 'title': 'Paracrine signaling', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['Paracrine signaling is a form of cell-to-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior of those cells. Signaling molecules known as paracrine factors diffuse over a relatively short distance (local action), as opposed to endocrine factors (hormones which travel considerably longer distances via the circulatory system), juxtacrine interactions, and autocrine signaling. Cells that produce paracrine factors secrete them into the immediate extracellular environment. Factors then travel to nearby cells in which the gradient of factor received determines the outcome. However, the exact distance that paracrine factors can travel is not certain.', 'Paracrine signaling is a form of cell-to-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior of those cells. Signaling molecules known as paracrine factors diffuse over a relatively short distance (local action), as opposed to endocrine factors (hormones which travel considerably longer distances via the circulatory system), juxtacrine interactions, and autocrine signaling. Cells that produce paracrine factors secrete them into the immediate extracellular environment. Factors then travel to nearby cells in which the gradient of factor received determines the outcome. However, the exact distance that paracrine factors can travel is not certain.\rhighlight sentence(s) containing evidence, not only the answer', 'Paracrine signaling is a form of cell-to-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior of those cells. Signaling molecules known as paracrine factors diffuse over a relatively short distance (local action), as opposed to endocrine factors (hormones which travel considerably longer distances via the circulatory system), juxtacrine interactions, and autocrine signaling. Cells that produce paracrine factors secrete them into the immediate extracellular environment. Factors then travel to nearby cells in which the gradient of factor received determines the outcome. However, the exact distance that paracrine factors can travel is not certain.']}}]}, {'provenance': [{'wikipedia_id': '4961951', 'title': 'Transcytosis', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['Transcytosis (also known as cytopempsis) is a type of transcellular transport in which various macromolecules are transported across the interior of a cell. Macromolecules are captured in vesicles on one side of the cell, drawn across the cell, and ejected on the other side. Examples of macromolecules transported include IgA, transferrin, and insulin. While transcytosis is most commonly observed in epithelial cells, the process is also present elsewhere. Blood capillaries are a well-known site for transcytosis, though it occurs in other cells, including neurons, osteoclasts and M cells of the intestine.', 'Transcytosis (also known as cytopempsis) is a type of transcellular transport in which various macromolecules are transported across the interior of a cell. Macromolecules are captured in vesicles on one side of the cell, drawn across the cell, and ejected on the other side. Examples of macromolecules transported include IgA, transferrin, and insulin. While transcytosis is most commonly observed in epithelial cells, the process is also present elsewhere. Blood capillaries are a well-known site for transcytosis, though it occurs in other cells, including neurons, osteoclasts and M cells of the intestine.\rhighlight sentence(s) containing evidence, not only the answer', 'Transcytosis (also known as cytopempsis) is a type of transcellular transport in which various macromolecules are transported across the interior of a cell. Macromolecules are captured in vesicles on one side of the cell, drawn across the cell, and ejected on the other side. Examples of macromolecules transported include IgA, transferrin, and insulin. While transcytosis is most commonly observed in epithelial cells, the process is also present elsewhere. Blood capillaries are a well-known site for transcytosis, though it occurs in other cells, including neurons, osteoclasts and M cells of the intestine.']}}]}, {'provenance': [{'wikipedia_id': '2457', 'title': 'Apoptosis', 'section': 'Section::::Abstract.', 'start_paragraph_id': 3, 'end_paragraph_id': 3, 'meta': {'evidence_span': ['Because apoptosis cannot stop once it has begun, it is a highly regulated process. Apoptosis can be initiated through one of two pathways. In the "intrinsic pathway" the cell kills itself because it senses cell stress, while in the "extrinsic pathway" the cell kills itself because of signals from other cells. Weak external signals may also activate the intrinsic pathway of apoptosis. Both pathways induce cell death by activating caspases, which are proteases, or enzymes that degrade proteins. The two pathways both activate initiator caspases, which then activate executioner caspases, which then kill the cell by degrading proteins indiscriminately.', 'Because apoptosis cannot stop once it has begun, it is a highly regulated process. Apoptosis can be initiated through one of two pathways. In the "intrinsic pathway" the cell kills itself because it senses cell stress, while in the "extrinsic pathway" the cell kills itself because of signals from other cells. Weak external signals may also activate the intrinsic pathway of apoptosis. Both pathways induce cell death by activating caspases, which are proteases, or enzymes that degrade proteins. The two pathways both activate initiator caspases, which then activate executioner caspases, which then kill the cell by degrading proteins indiscriminately.']}}]}]