Question

how the mussels made of..
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Answer 1

Answer:

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The shells of mussels have three different layers. The outer layer (called the periostracum) is made of organic material that may be yellow, green, brown, or black. The middle layer (prismatic layer) is made of elongate crystals of calcium carbonate (CaCO3).

Answer 2

Answer in Detail

Female mussels fertilize their eggs with sperm from a male and develop larvae called “glochidia”.

Once mature, females may release their glochidia into the water or even attract a fish to swim close with a lure. This increases the chance of glochidia attaching to a fish’s gills.

The glochidia takes nutrients from the fish for a few days or weeks in order to transform into a mussel (just like a butterfly out of a cocoon except the mussel sinks to the bottom instead of spreading its wings and flying away).

Mussel species rely on certain fish species to carry their babies through the water against river currents. Without a fish-piggyback ride, mussels would not be able to reproduce and populations would slowly vanish.Once settled into the bottom of rivers and lakes, freshwater mussels get to work doing what they do best: filtering water. Just like their saltwater cousins, freshwater mussels are great at eating small particles in the water. This is because most bivalves are uniquely adapted to use their gills to breathe but also collect and eat the nutritious phytoplankton other animals can’t. This ability to filter Earth’s fresh water gives value to our freshwater mussels, even if we can’t enjoy them on the half shell.

So while freshwater mussels parasitize fish gills in order to survive, they return the favor in spades by providing valuable ecosystem services such as filtering the water so it’s cleaner for other plants and animals to enjoy. Perhaps they aren’t so selfish after all…