The correct option is A, FEEDING HABIT AND MIGRATION. From the passage given above, it can be seen that seagulls are scavengers, they usually eat from garbage dumps while wild geese eat seeds and insects, thus they differ in feeding habit. In term of migration, seagulls does not follow seasonal pattern of annual migration while wild geese do. These are the contrasts between the two birds.
Solution:
According to the accepted current theory, known as the fluid mosaic model, the plasma membrane is composed of a double layer (bilayer) of lipids, oily substances found in all cells. The fluid mosaic model was first proposed by S.J. The fluid mosaic model describes the structure of the plasma membrane as a mosaic of components —including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character. Plasma membranes range from 5 to 10 nm in thickness.
Thus this is the required answer.