<span>The thickness of the tissue layer
that is in focus is called the focal plane. the plane through the focus perpendicular to the axis of a
mirror or lens. It is controlled by the exposure
angle. The focal plane thickness decreases as magnification increases. </span>
Answer:
The correct answer is a mantle.
Explanation:
A mantle refers to an essential component of the body of molluscs. It refers to a delicate covering produced from the body wall that at certain occasions get strengthened by calcium carbonate.
In various species of molluscs, the epidermis of the mantle discharges calcium carbonate and produces a shell over the entire body. The mantle encloses the stomach, heart, gonads, and intestines of the molluscs.
The correct answer is Certain flightless beetles have wings. Their wings are an example of an adapted structure.
These beetles have adapted structure in them and it is inherited from their ancestor's gene pool. as the time passes by the flightless beetles don't have wings as it was not needed but later become adopted due to environmental needs.
<h3>What is adapted structure?</h3>
Thick, hardened beetle wings, called elytra, cover the whole body and it has covered whole body of beetles. The adaptive features are inherited from their ancestor's gene pool.
Hence concluded that adapted structures in flightless beetles have wings. Their wings are an example.
To learn more about adapted structure refer to the link :
brainly.com/question/1213023
