Which enzyme is responsible for proofreading during replication?

What does it mean for a cell membrane to be selectively permable

In a cladogram, what occurs at a node? a derived trait appears. evolution is stopped. an ancestor dies. the cladogram ends. aa as s as ss what are the chances that their offspring will have sickle cell anemia? 0% 25% 50% 100%

What is the function of the nucleus in the euglena cells you observed?