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4 years ago

name three things that show evidence of evolution. write one sentence for each, explaining why it demonstrates evidence.

Biology

1 answer:

12345 [234]4 years ago

8 0

The answers are;

Fossils; present-day species have been shown to be closely related to some extinct species from the past as shown by fossils.
Molecular biology; biochemical analysis of biomolecules such as DNA and proteins show that species are related to one another and share a common ancestor.
Anatomy; Certain anatomical structures between species have shown convergent or divergent homology indicating sharing a common ancestry.

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Stickleback fish exhibit variation in a morphological trait known as gill rakers. Fish with long gill rakers are very good at ea

Scorpion4ik [409]

Answer:

c, disruptive selection

Explanation:

Disruptive selection is a term used to describe population genetic changes that simultaneously favor individuals at both ends of the distribution. When disruptive selection operates, individuals at the extremes contribute more offspring than those with intermediate characteristics, producing two peaks in the distribution on a graph.

In the excerpt shown in the question, long-gill-striped and gill-striped fish were favored by the selection process than intermediate-length striped fish. For this reason we can conclude that a disruptive selection was taking place.

6 0

4 years ago

Need a hypothesis for “How are proteins built from RNA”

Dima020 [189]

Hi!

Hypothesis:

<em>Proteins are built from the translation of messenger RNA (mRNA) molecules</em>

RNA, or ribonucleic acid, is a structure that is similar to DNA, except that it exists as a single strand, consists of a ribose sugar instead of a deoxyribose sugar and has the base uracil (U) instead of thyamine (T).

RNA is generated through transcription of the DNA molecule, resulting in a <em>complementary </em>molecule of the template DNA strand. For instance, if the sequence of the DNA was:

ATGCGCAGTTATTGCGAT

The corresponding RNA sequence will be:

UACGCGUCAAUAACGCUA <em>(complementary with U instead of T)</em>

<h3><u>From RNA to Protein</u></h3>

The RNA molecule in our case is known as the mRNA. After transcription the mRNA molecule is transported to the cytoplasm, where a ribosome binds to it for another molecule to translate the sequence. This translation is mediated by an RNA molecule known as the tRNA molecule which enters the ribosome to catalyze the reaction.

These molecules identify a sequence of 3 bases (codon) and for specific codon sequences, the tRNA allocates specific amino acid. For instance, for the codon <em>UCA</em>, the tRNA will allocate a <em>Serine residue.</em>

This translation process starts at specific three base sequences, known as start codons, and terminates at specific three base sequences known as stop codons.

In this manner, a sequence of amino acids respective to the mRNA codon sequence is synthesized, and as we identify proteins as chains of amino acids that are covalently linked together through peptide bonds, we can clearly see that proteins are built directly from RNA, and indirectly from DNA.

Hope this helps!

3 0

4 years ago

A student is working on a lab where they are trying to identify an unknown substance. the student decides to smell the solution

Rasek [7]

Complete question:

A student is working on a lab where they are trying to identify an unknown substance. The student decides to smell the solution by taking a big breath over the test tube. They immediately start to cough and their lungs are burning.

PRECAUTION:

RESPONSE:

Answer and Explanation:

Many chemicals might be recognized by their smell. Some of them might be inoffensive, some others might cause slight damage and some others might be very harmful to the person that inhales them.

In the exposed example, the solution probably damaged the respiratory tract, causing inflammation and irritation.

There are some issues to take into account to avoid an accident by inhaling a chemical:

<u>Precaution</u>:

Study the security rules of the laboratory
Always read the label of the substance
Ask the teacher or the person in charge, about the correct procedure
Proceed in the correct way, by driving the smelly vapors with your hand toward your nose. Never breathe directly over the test tube.

In case of accidents by inhaling you should:

<u>Response:</u>

Take the affected person out of the laboratory
Look for an airy place where the affected person might breath
Call an emergency service
Explain exactly what the affected person did and the chemicals that the person inhaled.

6 0

4 years ago

Why must scientists develop methods such as these to estimate population size?

mezya [45]

Population size and density are the two most important statistics scientists use to describe and understand populations. A population's size refers to the number of individuals (N) it comprises. Its density is the number of individuals within a given area or volume. These data allow scientists to model the fluctuations of a population over time.

5 0

3 years ago

All the following are characteristics of vitamin D except

Igoryamba

C. it’s synthesis is enhanced by use of sunscreen
- there are concerns that sunscreen might actually inhibit the body’s production of vitamin d

7 0

3 years ago