Answer:
d
Explanation:
Fishes are aquatic vertebrates having scales, pharyngeal gill slits and paired fins. ... Most fish are ectothermic ("cold-blooded"), allowing their body temperatures to vary as ambient temperatures change. fishes have scales that covers the skin of fishes. Thus, the correct answer is option D.
NaOH is not a compound because it contains three instead of two.
Answer:
on channel-linked receptors, G-protein-linked receptors, and enzyme-linked receptors.
The ability of cells to communicate through chemical signals originated in single cells and was essential for the evolution of multicellular organisms. In multicellular organisms, cells send and receive chemical messages constantly to coordinate the actions of distant organs, tissues, and cells. Cells can receive a message, transfer the information across the plasma membrane, and then produce changes within the cell in response to the message. Single-celled organisms, like yeast and bacteria, communicate with each other to aid in mating and coordination. Cellular communication has developed as a means to communicate with the environment, produce biological changes, and, if necessary, ensure survival.
<span>A. The nebula contracts and shrinks instead of expanding
</span><span>Nebula is the cloud of interstellar dust and gas that forms a star. It is collborately shaped during colliding and collapsing of the interstellar mediums this is influenced by the gravitational attraction of the atoms and particles in the entites. Hence, there are three types of nebular namely, are classical nebula, diffuse nebula, planetary nebular and supernova remnants.</span>
