That would be mutualism, i believe
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Explannnnnnnnnnnnnnnnnnnnnnnnation:
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.
It is D, Because cells are a very complex organism, they have a lot to do. It is like saying you have a play house.. but it is completely empty, that is if you chose A. They were not discovered in 1700s, they were discovered in 1665. and organisms are found in ponds, so they have cells too. So your answer is D.
Inhaled oxygen enters the lungs and reaches the alveoli. ... Oxygen passes quickly through this air-blood barrier into the blood in the capillaries. Similarly, carbon dioxide passes from the blood into the alveoli and is then exhaled.