The answer is A. - Prokatyotic cells lack a defined nucleus while eukaryotic cells do have one :) I loved learning about the cells in biology! But I noticed your question is worded a little differently so the nucleus would be the one thing a eukaryotic cell has that a prokatyotic cell does not...
A mutation is a permanent change in the DNA sequence of a gene. This can be beneficial if the change gives a new function to or improves the function of that gene.
<span>The above is a definition. But one must really define "beneficial". Some regard it as beneficial if it helps the specific individual who has it. Others would think it beneficial if it produced some survival advantage that insured more descendents for that individual. </span>
<span>It is the difference between a mutation that allowed for greater athletic ability, but a decreased desire for offspring, versus a more moderate athletic enhancement, but a greater desire for offspring. </span>
<span>The small percentage of ways to improve an organism, versus the near infinite ways of harming the organism, mean that most mutations are not going to be beneficial. At best, they will be "inconsequential" - such as a new shade of eye color, or a mole on a section of your skin. </span>
The populist notion of "powers" that can come from mutations is wildly inaccurate. Even assuming a minor power like the ability to see infra red radiation would take thousands upon thousands of mutations over vast amounts of time. A mutation for blindness is far more likely.
<span>It should also be noted that the traditional model of evolutionary theory no longer applies to man. We don't allow changes in our environment, and without such changes, there is no need for one trait more than another to predominate. After all, it is irrelevent that a mutation might allow for greater speed in running, when everyone drives a car.</span>
Answer:
Phytoplanktons are microscopic creatures that are primary producers of oceans. Phytoplanktons take carbon dioxide from atmosphere to make their food and then they are eaten by some other animals of oceans.
Phytoplanktons are present in huge numbers in oceans and have a great contribution to the carbon cycle because it is responsible for the transfer of carbon dioxide from the atmosphere to the oceans.
Most of the carbon is released through combustion by animals that eat phytoplanktons but some accumulate in the ocean floor because some dead phytoplanktons settles down in the ocean.
Answer:
Nerve agent
Explanation:
A nerve agent is a chemical in which on exposure to humans affects the functioning of the nervous system. These chemicals are known to disrupt the process by which messages are transferred to the organs from the nerve. This disruption occurs by blocking the activity of acetylcholinesterase, which is responsible for the catabolism of a neurotransmitter, acetylcholine.
On exposure to a nerve agent, the muscles of the body become paralyzed and early symptoms is production of excess mucous such as in runny nose, pupil constriction and also difficulty in breathing.
These agents are sometimes used in chemical warfare. Examples include sarin, tabun etc.
Answer:
A - Stigma
B - Anther
C - Filament
D - Style
E - Ovary
F - Petal
Explanation:
The above are the correct answers of the image drawn in the attachment.
These are parts of a flower.
A - Stigma: It is the head of the pistil. It contains a sticky substance that catches pollen grains from other pollinators.
B - Anther: This is the head of the stamen. It produces pollen grain.
C - Filament: It is a long slender part of the flower. It attaches the anther to the flower.
D - Style: It actually holds the stigma.
E - Ovary: It holds the ovule. Found at the base of the pistil.
F - Petal: It attracts pollinators to the flower.
