A
This should be considered a case of natural selection because humans were not selecting for particular desirable traits.
Explanation:
The individuals in the population who held even the slightest advantage in the tolerance of the oil spill had higher chances of surviving and passing their genes to the next generation. Fishes with low tolerance perished even before getting to maturity. Therefore with each generation, traits for oil tolerance in the population increased by natural selection enabling the population to evolve towards increased intolerance to oil over a period of several generations.
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Answer:
All of their functions are performed by a single cell.
Explanation:
Unicellular are those organisms whose body is madeup of one cell. In Unicellular organisms one cell perform all the functions and activities of the cell such as respiration, digestion, excretion and reproduction. Unicellular organisms reproduce asexually such as binary fission, budding and fragmentation etc. In Unicellular organisms, a single cell is divided into two equal parts and each part becomes a new organism.
B
Invasive plant species would end up harming the ecosystem in the long run. this is because it competes, usually unfairly , for space,sunlight and water and minerals.
Invasive species are very interruptive and often contribute to the extinction of endangered species in an ecosystem.
<span> a </span>mother<span> who is </span>Aa<span>, half of </span>her eggs<span> will </span>have<span> a chromosome which carries the A </span>allele<span>, and the other half will </span>have<span> a chromosome with the a </span>allele<span>. Similarly, half of the father's sperm will </span>have an A allele, and half willhave<span> the a </span>allele<span>.</span>
Answer:
Those capillaries that have endothelial cells tightly attached have an increase in cell-to-cell junctions, such as desmosomal junctions that are poorly permeable to substances.
These capillaries generally function as conductors or collectors and not as permeabilizers like the pulmonary capillaries that are fenestrated and allow a high passage of substances and gases.
The capillaries are waterproof and prevent the passage of substances or fluids such as in the blood-brain barrier that is very selective
Explanation:
The blood-brain barrier is too selective since it is not favorable for the organism that many fluids, drugs, substances or chemical compounds enter the brain space.
This is the reason why the vessels are waterproof and why pharmacology was challenged to invent drugs that could cross this barrier since it was considered impossible.
An example is dopamine, which in parkynson's disease the levo group is added to dopamine, thus forming levodopamine as a product, this is the only way that the drug crosses the blood-brain barrier and can pass the impermeable barrier generated by capillaries with endothelial cells that are close to each other or closely linked
