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3 years ago

The Silurian period occurred

Biology

1 answer:

anzhelika [568]3 years ago

8 0

<h3><u>Answer;</u></h3>

d. before the Neogene era.

<h3><u>Explanation;</u></h3>

<em><u>The Silurian Period was a third period of the Paleozoic Era that occurred from 443 million to 416 million years ago. This period occurred after the Ordovician Period and was then followed by the Devonian Period.</u></em>
Silurian period is the period that many biologically significant events took place. There was a widespread radiations of crinoids, continued priliferation and expansion of the brachiopods and also the oldest known fossils of coral reefs.

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What is the Advantages of boundaries of competence ethics

dimulka [17.4K]

Explanation:

The willingness to differentiate among possessing expertise and getting a serious level of respect is ethical competence. While applying policies to promote skill and qualifications to preparation and schooling for skilled careers, it is the phase outside technological competence that ethical competence must always be recognized.

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2 years ago

"ucture and properties of Matter

lapo4ka [179]

Answer:

Covalent bonds form when two atoms share valence electrons,

while Van der Waals forces cause an attraction between nonpolar

molecules

Explanation:

A covalent bond is said to be formed when two atoms of the same or different elements share electrons. In an ordinary covalent bond, each bonding atom contributes one valence electron while in a dative covalent bond only one of the bonding atoms provides the shared pair of electrons.

Van Der Waals forces is the major intermolecular interaction between non polar compounds. Van Der Waals forces " are caused by correlations in the fluctuating polarizations of nearby particles"(Wikipedia).

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3 years ago

Two cell divisions mitosis or meiosis

Troyanec [42]

Cell division is the process by which a parent cell divides into two or more daughter cells.[1]Cell division usually occurs as part of a larger cell cycle. In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell (mitosis),[2] and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half to produce haploid gametes(meiosis). Meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions. Homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in the last eukaryotic common ancestor.

Prokaryotes (bacteria) undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication.

For simple unicellular microorganisms such as the amoeba, one cell division is equivalent to reproduction – an entire new organism is created. On a larger scale, mitotic cell division can create progeny from multicellular organisms, such as plants that grow from cuttings. Mitotic cell division enables sexually reproducing organisms to develop from the one-celled zygote, which itself was produced by meiotic cell division from gametes. After growth, cell division by mitosis allows for continual construction and repair of the organism.[3] The human body experiences about 10 quadrillion cell divisions in a lifetime.[4]

The primary concern of cell division is the maintenance of the original cell's genome. Before division can occur, the genomic information that is stored in chromosomes must be replicated, and the duplicated genome must be separated cleanly between cells.[5] A great deal of cellular infrastructure is involved in keeping genomic information consistent between generations.

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3 years ago

Read 2 more answers

How was bacteria first discovered?

matrenka [14]

Bacteria were first observed by the Dutch microscopist Antonie van Leeuwenhoek in 1676

<u>-TheUnknownScientist</u>

3 0

3 years ago

What would be the most likely effect on the transcription of the trp structural genes for the mutation scenarios provided? mutat

blagie [28]

Answer:

I've responded to each scenario individually, please see below:

1. mutation that prevents ribosome binding to the mRNA

No transcription occurs

2. 5' UTR mutation that changes region 1 tryptophan codons into alanine codons

Transcription when alanine is low

3. mutation that creates a stop codon in region 1 of mRNA 5' UTR

Transcription occurs, a truncated protein will be made during translation

4. deletions in region 2 of the mRNA 5' UTR

Transcription occurs, region 1 and 2 might get paired together

5. deletions in region 3 of the mRNA 5' UTR

Transcription occurs, region 3 and 4 could combine to form a hairpin loop structure

6. deletions in region 4 of the mRNA 5' UTR

Transcription occurs, region 3 and 4 could combine to form a hairpin loop structure

7. deletion of the string of adenine after region 4 of the mRNA 5' UTR

Transcription occurs, however, it will not be as stable a molecule because of losing its polyA tail

Hope that answers the question, have a great day!

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3 years ago

Read 2 more answers