Marin’s distinctive geography and wildlife offer unique educational opportunities — with no term papers required, and field trips a given. Offered through the Point Reyes National Seashore Association Field Institute, the 3½-hour class involves vigorous activity and requires advance registration ($50), after which participants will be sent the exact location. The Marine Mammal Center in Sausalito also provides an alternative classroom for nature lovers with Marine Science Sunday, a series of free, hour-long, interactive classes the second and fourth Sunday of each month. The May 28 session focuses on endangered and threatened species such as Hawaiian monk seals, blue whales and fur seals, while June 11 and 25 sessions explore marine mammal sounds. The Sunday classes, which include multimedia presentations, are offered at noon and 2 p.m., with specially themed docent-led tours available at 11 a.m., 1 and 3 p.m.