Which of the following observations darwin shape his concept of descent with modification?
a. species diversity declines farther from the equator.
b. fewer species live on islands than on the nearest continents.
c. birds live on islands located farther from the mainland than the birds’ maximum nonstop flight distance.
d. south american temperate plants are more similar to the tropical plants of south america than to the temperate plants of europe.

The correct answer will be option-D.

Explanation:

Darwin is best known for his theory of evolution which he proposes after collecting the specimens of plants and animals on his voyage.

He observed the similarity and differences of the morphological pattern as well as the species present in the area. On the basis of his conclusions, he suggested that organism get traits from their parents and species to change over time also called descent with modification.

One of the evidence that supported his concept is that he observed plant species in South America and found that these species closely resembled the species of the tropical regions of South America rather than species of the temperate region of Europe as the habitat was same.

Thus, option-D is the correct answer.

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it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.