While a constant supply of freshwater happens by itself in natural streams, an aquarium is by definition, a closed system. So here, man has to help out in order to provide new..
Answer:
Hope the above picture might help you :)
Answer:
A. Porifera
Explanation:
Parazoan is a sub-kingdom of animal consisting only of the phylum of sponges (porifera), having two tissue layers only and lacking a nervous system and true digestive cavity.
They have certain characteristics like: sponges are marine, but there are some freshwater sponges that enjoy their water without salt. Most sponges do not have any type of symmetry, but some are radially symmetrical and they come in a variety of shapes, colors, and sizes, they are multicellular, heterotrophic and lack cell walls. Unlike other organisms, sponges lack true tissues and organs.
The mesohyl functions as an endoskeleton in most sponges, and is the only skeleton in soft sponges. This mesohyl is stiffened by mineral spicules, by spongin fibers or both.
Answer:
Option C, At a subduction zone, oceanic crust is forced deep into the Earth.
Explanation:
At sub-duction zone, the dense oceanic plates coincides with the less dense continental plates and thus sink below the continental plates. Sometimes these oceanic plates being dense, sink to greater depth with in the earth’s mantle. The sub-duction zone causes earth quakes of high intensity when oceanic crust penetrates to greater depths of earth crust as they tend to change the rheology of the earths’ mantle and also causes bending of plates
Hence, option C is correct
thymus plays important role by development of a normal, healthy immune system. thymus function is to generate mature lymphocytes
In other words, white blood cells that help fight of illness in the immune system.
sorry if I am wrong.
