Which social network is available in the Lightning Experience and Salesforce1?

At Universal Containers, the Account object has a Master-Detail relationship with an Invoice custom object. The App Builder would like to change to a lookup field, but is not able to do so. What could be causing this?

Universal Containers wants some enhancements on its Opportunity page layout to improve efficiency and collaboration.
Which two solutions should an app builder suggest to help meet these requirements?
Choose 2 answers