Fish breathe by drawing water in their mouths and forcing it out of the body via a number of gill slits. The gill slits are rich in blood vessels, enabling the direct absorption of oxygen. While all fish have gills, some fish are also able to extract oxygen from the air via gulping.
Most fish have swim bladders that are permanently sealed, but other fish have swim bladders that can hold varying amounts of air. Salmon have open swim bladders, and they must gulp air at the surface to keep them full. Some fish, such as sharks, lack swim bladders entirely. This causes them to sink if they do not maintain forward motion.
Fish have fins that are adapted to their lifestyle. Some have evolved into long, barbed structures, suitable for defense. Other fish have fins suited for achieving great speed or for walking along the bottom of the ocean.
Answer:
Hormones signal the mammary glands in your body to start producing milk to feed the baby. But it's also possible for women who have never been pregnant — and even men — to lactate
Explanation:
read the answer please
<span>The communication in which molecules move from one place to another inside of a cell is intracellular type of communication, molecular signal. Answer:B
The molecular signals can be one of the following four types:
</span>Endocrine, Paracrine, Neuronal and Juxtacrine.
Diminishes,
A perfect example is humans on the earth, with our population rapidly growing eventually the earth will not be sufficient enough to humans.
