How do you classify the different biological zones in rivers and streams:
lengthwise:
width wise
vertically

Which anatomical feature would you expect to find in the fossil remains of a nocturnal species?

This is a 2017 topographic map of puerto rico in the united states, and i'm sorry that people there have suffered such a disaster. i want to ask, what do the yellow dots and areas represent on this graph? and the blue area and the little blue circle, and the little blue sign that looks like a signal tower, what do they stand for?

What is one early technological advance that shaped culture? a the use of fire b the discovery of arable land c family units. d migration