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.
Answer:
Option-B
Explanation:
Phototropism refers to the movement of plants in response to light. The mechanism of phototropism involves the photoreceptors which respond to a different wavelength of light: the phytochromes to red light, cryptochromes to blue light and the phototropin to the UV light.
Plants integrate the signals obtained from these receptors and then activates the gene which will be involved in the phototropism.
The gene could be the production of the auxin hormone and the PIN proteins which helps in the distribution of the auxin in the plants. Due to the production of this hormone and its distribution in the shoot, the grass tips bend towards the light.
Thus, Option-A is correct.
The Nucleus is the hub of the cell, the heart and soul of the cell. As much as a quarterback is in a football team. The Nucleus is what keeps the cell going and a cell wouldn't exist without a Nucleus. Hope this helped, have an amazing day :)
Answer:
Kussmaul respirations indicates the condition of acidosis and diabtetes ketoacidosis
Explanation:
Kussmaul respiration refers to the labored and deep breathing pattern. Adolph kussmaul introduced the term Kussmaul respiration.
This respiration refers to the form of hyperventilation in which the amount of carbon dioxide is decreased in the blood. The metabolic acidosis alters the normal pattern of breathing and results in rapid and shallow breathing. The Kussmaul respiration is most common in ketoacidosis.