Why must vitro observation be confirmed in vivo

In a cladogram' when does a group of organisms branch off

Land conservation is a worldwide priority. there are several methods to prevent the loss of land due to a variety of reasons. which method is not a way to conserve land? a) sea walls b) rainwater harvesting c) limits on clear cuts of forests d) cut and burn methods of clearing land

Wich is not standing in the way of astronomers getting a good view of different star