The structure of the skin is an effective barrier against bacteria. The multiple layers of epidermis, while can be invaded by foreign organisms, has a high turnover rate which means it is constantly shedding, therefore even the bacteria is shed protecting the body. Lastly, the skin's lipids maintain an acidic pH which slows and stops growth and replication of bacteria.
The correct answer is transitional.
Gerobatrachus refers to an extinct genus of amphibamid temnospondyl, which thrived in the initial Permian, that is, about 290 mya, in the region, which is now known as Baylor County, Texas. The transitional form of fossils are those that demonstrate the intermediate form between the two distinct living species, it could be in a form of an ancestor and its descendants. It is considered that the frogs and salamanders have evolved from a common ancestor of primitive amphibian tetrapod subclass known as Temnospondyli.
Answer: Sea stars move using a water vascular system. Water comes into the system via the madreporite. It is then circulated from the stone canal to the ring canal and into the radial canals.
Explanation: The radial canals carry water to the ampullae and provide suction to the tube feet.
Answer:
RNA molecules are made of nucleotides. (Ans. C)
Explanation:
RNA, which is also known as ribonucleic acid is found in cytoplasm of the cell, and synthesized in the nucleus. It is shorter, and a single stranded molecule. It is composed of one or more nucleotides which are linked together by phosphodiester bonds.
In RNA, the ribonucleotide contains pentose sugar ribose, four nitrogenous bases (A,U,C,G), and a phosphate group. RNA plays many types of role in cells, but mainly involved in the translation process, and it's regulation which is known as protein synthesis.
