A new building in Arsenal Yards could add to Watertown’s growing presence in the life sciences industry. The proposal calls for a mostly glass building on the southeastern section of the property facing the Charles River. It would have either eight or nine stories, stand 130 feet high and have approximately 155,000 square feet. Each floor would have between 16,000 and 20,000 square feet, likely supporting one or two tenants on each floor. The building would also include a garage.