l ADR said told difference between two animals -DR find similarity between dinosaur, bird and mammal -bone traps fiber and vessel -HC appear as bone mature -texture and canal deduce bone growth -high metabolic rate indicated endothermic l Evidence come under fire -TO asserted canal from exertion -experiment lizards compared bones -show same channels , suggested link with active lifestyle l Distinction draw exercised and une- -one ran on treadmill had canal -exercise shape bone micro structure l Exercise, bones strained -occasionally form tiny stress fracture -bone need to remove crack l rule of remodeling -canal tells animal was active -not tell warm- or cold-blooded
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