Dorsal means back as in the back area. Example~ Many dolphins have a pronounced beak and all have a central dorsal fin and sharp teeth for feeding, mainly on squid and fish.
Mutualism, The question is asking us to choose the correct symbiotic relationship.
There are THREE types of Symbiosis.
SYMBIOSIS is a relationship between two organisms.
I'll give you a quick run-through of each one.
1. MUTUALISM is where both organisms benefit, from one another.
2. COMMENSALISM is where one organism benefits, and the other is totally unaffected.
3. PARASITISM is where one organism benefits, while the other is harmed.
2.66667 m/sec use the equation for speed d/t = s