Primary sources means that it is original article or book created by an individual or sometimes a group of people. What types of primary sources are available? It might be surprising to know that a novel is a primary source. Other types of primary sources are paintings created by the artist. If it were a photocopy of the painting, then it would be a secondary source. Some other primary sources are letters, films, short stories, plays, poems, photographs, court cases, journal articles, newspaper events, and speeches. For instance, a speech by President Bush would be a primary source.
Secondary sources are sources that are written about primary sources. Secondary sources analyze, interpret, and discuss information about the primary source. If a magazine writer wrote about the speech President Bush gave on September 11th, it would be a secondary source. The information is not original, but it is an analysis of the speech.
Answer:
Please find the explanation below
Explanation:
The lac operon is a unit containing structural genes and a single promoter in bacteria such as E.coli. A repressed gene is a gene in which the expression has been inhibited or prevented from occuring.
In E.coli, the lac operon contains three structural genes viz: lacZ, lacY and lacA, that codes for proteins capable of degrading lactose sugar for energy purposes. In the presence of lactose, the expression (transcription and translation) of these three lac genes occur normally.
However, in a scenario where lactose is absent in the bacterial cell, the expression of the lac gene in the lac operon is inhibited. This inhibition/repression is done by LAC REPRESSOR, which is a transcription factor/protein that binds to the OPERATOR region of the lac operon and prevents RNA polymerase (transcription enzyme) from binding to the PROMOTER region.
Once RNA polymerase is prevented from binding to the promoter, transcription (gene expression) does not occur. Hence, in the absence of lactose sugar, the lac operon is a repressed gene.
Answer:
A biologist discovered a young, four-legged animal. The animal had lungs, seemed to fertilize internally, and its outer surface was covered with scales. In which class of animals is the biologist likely to place the animal?
reptile
Answer:
Hyphae; mycelium.
Explanation:
Fungi can be defined as living microorganisms that are eukaryotic in nature and are able to reproduce using both means of reproduction i.e both asexually and sexually. Also, fungi do not have chlorophyll but are of great importance to the human world both scientifically and practically.
A thallus can be defined as the vegetative or bodily structure of fungi. Thus, the various forms of fungi are;
I. Yeast.
II. Mushroom.
III. Mold.
A mold is typically multicellular (has more than one cell) and filamentous in nature. The thallus of a mold consists of long, branched, threadlike filaments of cells called hyphae that form a tangled mass called a mycelium.