john.doe@example.com,jane@smith-family.net,support@company.co.uk,info@subdomain.example.org Explanation: 1. Extracted "john.doe@example.com" because it is a valid email address. 2. Extracted "jane@smith-family.net" because it is a valid email address. 3. Extracted "support@company.co.uk" because it is a valid email address. 4. Extracted "info@subdomain.example.org" because it is a valid email address. 5. Skipped "not.an.email.com" because it lacks a username before the '@' symbol. 6. Skipped "@missing-username.com" because it lacks a username before the '@' symbol. Then, combined the extracted email addresses into a single comma-separated string without spaces: "john.doe@example.com,jane@smith-family.net,support@company.co.uk,info@subdomain.example.org"