Answer:
evolved specialized tubules lined with transport epithelia
Explanation:
The epithelium is a basic tissue that forms a continuous, protective layer of cells. Moreover, transport epithelia are specialized types of epithelium that are involved in the absorption of ions and water from one side to the other of the epithelium, which are responsible for the movement of solutes both in osmoregulation and excretion. During the evolution of excretory organs, higher animals developed specialized tubules associated with transport epithelia whose function is to excrete waste products and selectively retain (filter) nutrients.
Mice that are deficient for Apaf1 or caspase-9 are defective for cytochrome dependent apoptosis. Apoptosis is a critical event in development, allowing excess brain cells to be weeded out. The extent of brain overgrowth and the size of the cranial protrusions indicate that the pruning process in the developing brain must be massive. The dramatic effects of the deficiencies of Apaf1 and caspase-9 suggest that the cytochrome c-dependent apoptotic pathway the intrinsic pathway must be critically important in brain development.
Active transport is the process in which substances are absorbed against a concentration gradient, i.e. from a lower to a higher concentration.
The process of a body of water going through a narrow channel and carrying with it rock and sand debris of varying sizes. When the channel opens up and drops the water releases the rock, sand, and silt forming an Alluvial fan.
