Blue would be the hottest. And red would be considered the coolest.
Rose is an example of a producer.
In this question, there are no options given to choose from. So i would answer this question based on my knowledge. The most likely cause of the observed variation is adaptation and evolution. The birds of that island adapted to the food source and then they evolved as per the requirement of the place and food source.
The correct answer is option C. Endocrine glands secrete hormones into the bloodstream because endocrine glands are ductless and the exocrine glands have ducts so they secrete their hormones into the ducts.