Behavioral psychologist tries to train a bird to climb a tree to get a reward of a piece of fruit. At first, the bird learns how to climb the tree with its legs and beak. After a while, it starts flapping its wings and hopping around before it starts to climb. Eventually, the bird flies up to the piece of fruit, even though that prevents it from getting the fruit. According to the Brelands' analysis of biological constraints, the bird is demonstrating .

b. that it was reverting to behavior that was instinctual for it.  

Explanation:

When observing the animals, Keller and Marian Breland saw how sometimes they learn some behaviors ore easily than the other times. They noticed how animals will likely revert to instinctual behavior rather than learned one when they are trying to supply themselves with food. Even when one pattern of behavior is learned for years, once an animal is under the primal need of food, they are returning to their instinctive behavior.

They called this phenomenon as instinctive drift or instinctual drift and the pair called it "a clear and utter failure of conditioning theory."

when your a dog and you need a bone.   go and eat a rabbit

marginal cost is a microeconomic measure that us to evaluate the extent to which the level of production of a good is sustainable in accounting, that is, to how many quantities the company plans to profit from the production of the good.

the concept of marginal cost is simple, it means the cost of producing one more item. for example, in the case of pies, the marginal cost is the cost of producing one more pie than those that have already been produced.

it is important to understand that productive activity influences marginal cost. the marginal cost of some goods can be very high, while others may be insignificant. for example, the marginal cost of producing an extra plane is very high. already the marginal cost of a water company to provide 1l more water is derisory.

in the case of pies, the cost involves the inputs, the labor and the fixed cost, which involves the fixed space of the bakery. the level of production initially has the marginal cost decreasing because there is space and manpower available. however, to produce more you have to hire more workers and buy more inputs. if physical space is limited, workers will conflict with places, inputs and their productivity will decrease, meaning there is an optimum point of production for each level of space and manpower. from this point on, the productivity of the workers will be getting smaller because of lack of space, so that the marginal cost of producing one more pie will be increasing. so, although you have not posted the chart, but if you have the answer, you can see that my explanation goes according to the marginal cost curve that will increase from the 4th pie, answer (c).