Irrigation system gave the ancient civilizations fertile land which helped crops grow. It also allowed for ease of watering which made the process of farming faster.
        
             
        
        
        
Complete question: A phylogenetic tree shows that birds and crocodiles share many features. A hypothesis based on this tree predicts that these features are present in a common ancestor. Which of these predicted traits is supported by fossil evidence?
A) four-chambered heart
B) singing for territory
C) eggs and nests
D) singing to attract mates
Answer: (c) eggs and nests
Explanation:
A hypothesis based on phylogenetic tree shows that birds and crocodiles have ancestral connection. Fossil evidence shows that their common ancestor exhibit oviparity as a means of reproduction (i.e. laying of eggs and embryo develops within the egg), and also housed their eggs in the nest for protection against predators and other important reasons.
 
        
             
        
        
        
Answer:
Krill
Explanation:
All animals in the Antarctic depend on krill, very small crustaceans, for their survival.