; (2) the increased risk of the disease among those exposed to toxic substances during active military, naval, or air service; and (3) whether there exists a plausible biological mechanism or other evidence of a causal relationship between the exposure and the occurrence of the disease. (e) Cooperation of Federal agencies The head of each relevant Federal agency, including the Secretary of Defense, shall cooperate fully with the Academies in performing the services covered by this section. (f) Recommendations for additional scientific studies (1) In general Under an agreement between the Secretary and the Academies under this section, the Academies shall make any recommendations for additional scientific studies to resolve areas of continuing scientific uncertainty relating to the exposure of humans to toxic substances. (2) Considerations In making recommendations under paragraph (1), the Academies shall consider— (A) the scientific information that is available at the time of the recommendation; (B) the value and relevance of the information that could result from additional studies