It would be that they are made from cooling of lava or magma because they form from magma underground unlike sedimentary rocks
When the air pressure within the alveolar spaces falls below atmospheric pressure, air enters the lungs (inspiration), provided the larynx is open; when the air pressure within the alveoli exceeds atmospheric pressure, air is blown from the lungs (expiration).
They both have a nucleus along with other complex membrane bound organelles.
The correct answer is the Cell Death.
The cell death may be the result of the natural process of old cells dying and or might be as the result of different factors like disease or localized injury. The cell death is necessary for the survival of an organism, for its development and growth. There are different types of cell death and different classifications of them. Most commonly it is classified by its s morphological appearance, so it may be apoptotic, necrotic, autophagic or associated with mitosis.
