Answer:
Physical characteristics.
Explanation:
She knew what type of birds they were based on their physical characteristics.
She didn't see their nests, or see them eat, and she didn't test and analyze their genetics, so a is the correct option.
The correct answer is tab.
Cross section<span> is a cut at an angle perpendicular to its axis so its interior </span>structure can be viewed<span>.
</span>A structural section describes a house's foundation assembly. This structural section refers to the section of the assembly that is horizontal and it shows the basic shell of the house.