What happens if the ui.json file is empty?

A company's Salesforce org has multi-currency enabled. This company's business intelligence team used Einstein Analytics to build a dataflow that creates a dataset, "OpportunityDataSet". This dataset is populated with data extracted from the standard object, Opportunity. One of the extracted fields is the standard field, Amount.
If a user explores the "OpportunityDataSet" in Einstein Analytics, in which currency will the Amount values be shown?

What can you change in a Compare Table formula column?

Why would you use the Actions menu in a chart?

A consultant built an Einstein Analytics dashboard for a shipping company. The dashboard displays data from several data sources- The consultant enabled data sync (replication) to increase the speed of data refreshing from these sources.
What is the maximum number of dataflow definitions available in this situation?