Which key morphological feature is used to classify organisms as mammals
a. the presence of fur
b. fertile offspring
c. mammary glands
d. two-legged upright posture

Which macromolecules are polymers made of nucleotides (a) fatty acids (b) nucleic acids (c) carboxylic acids (d) amino acides

Dr. kaylan is an ecologist who studies bird behavior. she sets up an experiment to test which type of food crows are most likely to eat when given a choice between walnuts, corn, and sunflower seeds. to perform her experiment, dr. kaylan places three food bins in an area frequented by cows. each bin contains one of the three food types. then, she measures how much of each food type is eaten every day for a month and summarizes the results of her experiment in the pie chart below. based on her results, dr. kaylan concludes that crows choose to eat corn more frequently than other food sources because it has a higher nutritional value. what is a reasonable alternate conclusion that can be drawn from dr. kaylan's data

Why do we perceive objects as retaining their brightness under different lighting levels?