Coral reefs are part of the marine and oceanic ecosystem that are hard and made up of calcium carbonate. Planulae is not the major structure of coral reefs.
<h3>What are coral reefs and Planulae?</h3>
Coral reefs are the hard calcium structures that are of three major types barrier, fringing and atoll. They feed on the planktons and algae that are the small structures inhabiting them.
Planulae is a freely swimming larvae of the jellyfish and other species of Ctenophores. They are solid, flat and have cilia over their body.
Therefore, option a. Planulae is not a structure or type of coral reef.
Learn more about coral reefs here:
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Answer:
the 3rd one and the last one
Explanation:
1. Pulmonary Blastomycosis: is transmitted from inhalation of spores from dust and iscaused by Blastomyces dermatitidis. It targets the lungs and shows signs of fever,chills, joint pain, muscle pain and headache and cough.
2. Histoplasmosis:caused by Histoplasma Capsulatum that is transmitted by theinhalation of spores near bird or bat droppings, it targets the alveolar in the lungs andshows signs related to the flu, and chronic cough.
3. Aspergillosis: this is caused by the organism aspergillus spp. It is transmitted by theinhalation of spores from moldy vegetation and targets the lungs. The symptoms arecough with blood, wheezing, fatigue, shortness of breath, fever and chills, chest pain,face swelling and skin lesions.
Answer:
Option 2: Spiracles.
Explanation:
Cartilaginous fish (also called Chrondricytes) have a skeleton of cartilage, instead of bone. There are two subclasses - Elasmobranchii and Holocephali. Sharks, rays, skates and sawfish are elasmobranchs while chimeras are holocephali.
Here’s a list of features of cartilaginous fish in comparison to bony fish:
1. Cartilage skeleton: unlike bony fish that have a skeleton made of bones (just like other terrestrial vertebrates), the skeleton of cartilaginous fish is made of cartilage.
2. Spiracles: this is a modified gill of sorts, it aids with respiration and is found slightly behind each eye. It leads directly to the mouth. Most cartilaginous fish possess this organ (exceptions are present, such as hammerhead sharks). Bony fish do not possess spiracles.
3. Ampullae of Lorenzini: absent in bony fish, these organs are electroreceptors that form a network of pores filled with a form of jelly that can transmit electrical signals. It allows the cartilaginous fish to sense electric fields in the water (such as the movements of a fish struggling), magnetic fields and temperature. Some bony fish such as sturgeon and lungfish may possess these organs, however research is still ongoing.
4. Claspers: male cartilaginous fish possess an organ known as claspers at their pelvic fin. This is used during reproduction to transfer the sperm into the female for fertilisation. As such, internal fertilisation occurs in cartilagonous fish. Bony fish do not possess this organ, and external fertilisation occurs.
There are many other characteristics that differentiate cartilaginous fish from bony fish. They're an extremely fascinating group of animals that unfortunately, is decreasing in numbers. Very little is known about many of these animals, so it is important that we do our best to conserve the sharks, rays, sawfish and chimeras before we lose them forever.
