Marine debris is defined as any man-made solid material that goes into waterways either directly or indirectly. Eighty percent of the marine debris comes from the land-based sources. Examples of marine debris are soda cans, plastic bag, cigarette waste. Anything that ends up in a water body that has a potential in harming the marine life is a marine debris.
Answer:
Explanation:
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Amphibians have three heart chamber and they lay eggs so
AMPHIBIAN
Answer:
False
Explanation:
The histones that are more positively charged, tight hardly to negatively charged DNA. So, enzymes, such as acetyltransferases, that reduce the positive charge of histones promote transcription.
Chromatin structure and its modifications can change the package of the DNA and consequently, alter the gene expression. The most common modifications of the chromatin are covalent modifications such as acetylation/deacetylation (by acetyltransferases and eacetylases), methylation (by methyltransferases), and phosphorylation (by kinases). This is the way of gene expression regulation.
The effects of modifications are different, for example methylation promotes condensation of the chromatin and as a consequence, prevents binding of transcription factors to the DNA (transcription is repressed).
Acetylation loosens the association between nucleosomes and DNA (because it neutralizes the positive charge of histones) and consequently promotes transcription. Deacetylation is a process opposite to acetylation.
