Material through which water flows is permeable. This material can be either natural or artificial. Naturally permeable material can be clean sand and gravel for example, or a sandstone and in the latter case the sandstone can have both porosity which is not synonymous with permeability as the pores must be connected to be permeable. An impermeable membrane could be used to line ditches for example to prevent leakage near mines.
The aerodynamic shape and lightness of the blue shark body allow it
to move “elegantly” across the oceans. It exhibits countershading like
many other sharks. The upper part is an indigo blue tone while the
ventral and the sides are white.
It has a long caudal heterocercal fin. The second dorsal fin measures
almost half the size of the first and its pectoral fins are unusually
long compared to other sharks. Its eyes are large, its teeth are
triangular, and it has a conical snout.
It reaches a length ranging from 3.8 to 4 meters and weighs about 240
kilograms. This species presents slight sexual dimorphism since the
female tends to measure little more than 1 meter in comparison with the
male.
Las Ciencias de la Tierra o Geociencias conciernen y engloban las disciplinas que estudian la estructura, morfología, evolución, y dinámica del planeta Tierra. Constituye un caso particular de las ciencias planetarias, que se ocupan ellas del estudio de los planetas del Sistema Solar.
