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jasenka [17]
3 years ago
9

Which of the following is a chemical change?

Biology
2 answers:
irga5000 [103]3 years ago
8 0
The answer is letter D!
Dmitriy789 [7]3 years ago
3 0

Answer:

D. silver tarnishing as the silver metal reacts with sulfur​

Explanation:

A chemical change occurs when the identity of a substance is changed. Silver tarnishing is a chemical change because silver and sulfur react to form a new substance, silver sulfide. In the other examples, the substances have not changed their identity and only physical changes have occurred.

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What do you think will happen to the ph and pco2 levels with hyperventilation?
umka2103 [35]

It will increase blood pH. This is because pCO2 also reduces. pCO2 is critical in the <span>maintenance of blood pH. Dissolved CO2 from respiring tissues dissolves in blood to form carbonic acid. The carbonic acid partially dissociated into H+ ions and its conjugate base (bicarbonate ions). Carbonic anhydrase catalyzes the formation of carbonic acid (in tissues) and vice versa (in the lungs). In the lungs, the carbon dioxide is expelled.  </span> 






7 0
4 years ago
I have no clue.....hate biology tho :3
omeli [17]
The answer is B.....
4 0
3 years ago
MOST organisms in any ecosystem are
IrinaK [193]

Answer:

producers (plants)

Explanation:

plants are the most common

8 0
4 years ago
Classify each description as true of introns only, exons only, or both.A-present in eukaryotic genomesB-generally absent from ba
maxonik [38]

The right answers are:

A-present in eukaryotic genomes ==> Both exons and introns

B-generally absent from bacterial genomes ==> Introns

C-part of the final mRNA strand ==> Exons

D-code for an amino acid sequence ==> Exons

E-removed from initial mRNA strand prior to translation ==> Introns

F-present in the DNA used as the template for transcription ==> Both exons and introns

In the genes of eukaryotic organisms, the exons are the segments of an RNA precursor that are conserved in the RNA after splicing and that are found in mature RNA in the cytoplasm. The segments of the RNA precursor that are removed during splicing are called in opposition to introns. Exons are mainly found in messenger RNAs (mRNAs) encoding proteins. Some mRNAs may sometimes undergo an alternative splicing process in which one or more exons may be excised or some introns preserved in rare cases.

6 0
3 years ago
Describe both innate and acquired immune systems and the importance of vaccines.
lbvjy [14]

Answer:

Innate immunity is a non-specific immune system which provides defence against any pathogenic microorganism in early stages. It includes physical barrier such as skin, chemical barriers such as saliva, tears, et cetera, phagocytic cells such as macrophages, et cetera.

Acquired immune system is the one which develops after exposure to pathogen or antigen. It is highly specific in nature. It includes B-lymphocytes and T-lymphocytes. It includes the production of antibodies.

Vaccines are used to develop acquired immunity in people. The process is termed as vaccination or immunisation. Heat-killed or weakened pathogen or antigen is inserted into a person after which a person develops antibodies and memory cells against that pathogen or disease. So, the immune system acts more vigorously against that pathogen in secondary infection.

Thus, a person becomes immunised.

3 0
3 years ago
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