Echinoderms, they are among the most common invertebrate animals in the marine environment of virtually any part of the world, among them we can find species such as sea cucumber , salmon and cod fish, they have chamois cloth like outer layer, then we have the Crinoids, another example of marine species with feather, popularly they are called sea lilies and feathery stars, they have a solid calcite skeleton; they were so abundant in the paleozoic seas that their remains formed large limestone thicknesses.
hi, good morning, where are you from? I'm from France
Answer:
A plant cell is surrounded by rigid cell wall whereas animal cell does not have cell wall. Presence of a large vacuole in plant cell, which is small in animal cell. Plant cells are larger than animal cells. Plant cells have plastids whereas animal cells do not have plastids.
<span>achievement
</span>A test that measures a person's knowledge in a specific subject area is a(n) achievement test.
Answer: See attached picture.
Explanation:
DNA or deoxyribonucleic acid is the name for the molecule that contains the genetic information in all living things. This molecule consists of two strands that wind around each other to form a double helix structure.
The basic unit of nucleic acids are called nucleotides, which are organic molecules formed by the covalent bonding of a nucleoside (a pentose which is a type of sugar and a nitrogenous base) and a phosphate group. So each nucleotide is made up of a pentose sugar called deoxyribose, a nitrogenous base which can be adenine (A), thymine (T), cytosine (C) or guanine (G) and a phosphate group.
<u>What distinguishes one polynucleotide from another is the nitrogenous base</u>, and thus the sequence of DNA is specified by naming only the sequence of its bases. The sequential arrangement of these four bases along the chain is what encodes the genetic information, following the following criterion of complementarity: A-T and G-C. So the sequence of these bases along the chain is what encodes the instructions for forming proteins and RNA molecules. In living organisms, DNA occurs as a double strand of nucleotides, in which the two strands are linked together by connections called hydrogen bridges.
The chemical convention of naming the carbon atoms in the pentose nucleotide pentose numerically confers the names 5' end and 3' end ("five prime end" and "three prime end" respectively). The 5'-end designates the end of a DNA strand that coincides with the phosphate group of the fifth carbon of the respective terminal deoxyribose. A phosphate group attached to the 5'-end allows the ligation of two nucleotides; for example, the covalent bonding of the 5'-phosphate group to the 3'-hydroxyl group of another nucleotide, to form a phosphodiester bond.