What important temperatures does the celsius scale use for a basis

What must be true for natural selection to heppen

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%

Plz ! what does it mean for an allele to be dominant?