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3 years ago

Why do scientists think that birds evolved from dinosaurs?

Biology

2 answers:

lisabon 2012 [21]3 years ago

8 0

Answer:

Modern birds are descended from a group of two-legged dinosaurs. Based on these life-giving characteristics, scientists have concluded that theropods were ancestral birds. Perhaps the bird evolved from dinosaurs by accepting animal's pattern.

Explanation:

The respected scientific consensus is that the birds are Teherod dinosaur groups that continued living during the Mesozoic era. The velociraptor has a skull simmilar as the coyote and the brain of an pigeon.

Of course, these are just theories. It is not proven that birds evolved from dinosaurs, but many characteristics are leading to this theory, especially after the discovery of the primitive bird Archeopterik in Germany.

Yanka [14]3 years ago

3 0

Answer: birds and dinosaurs have more efficient hearts and lungs than mammals

Explanation:

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What best defines a population?

mrs_skeptik [129]

Answer - Consists of all the individuals of a species that live together in one place at one time.
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4 years ago

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Which of the following is not a component of the hepatic triad found at the edges of a liver lobule?

goldenfox [79]

Answer: c) central vein.

Explanation:

The liver is an organ that is present both in humans and in vertebrate animals. It secretes the bile, essential for the digestion of fats, and it also has many other functions, including the synthesis of plasma proteins, storage of vitamins and glycogen and detoxifying function. It is responsible for removing various substances from the blood that may be harmful to the body, including alcohol, making them harmless.

The liver is divided by the sickle cell ligament into two main lobes, right and left. There are two other smaller lobes, the square lobe and the caudate lobe.

The hepatic triads are triangular areas located at the angles of the hepatic lobules, made up of a lax conjunctive stroma. They contain a branch of the hepatic artery (that irrigates the liver), a hepatic portail vein (a thick blood vessel that carries blood from the gastrointestinal tract and spleen to the liver so that nutrients are metabolized) and a bile duct (transports bile into the small intestine). Therefore, it does not contain a central vein.

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3 years ago

Binary fission is a proses through witch

vredina [299]

Binary fission ("division in half") is a kind of asexual reproduction. It is the most common form of reproduction in prokaryotes and occurs in some single-celled eukaryotes like Amoeba and Paramecium.

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3 years ago

the average temperature in a certain Valley is usually higher than that of the surrounding Countryside this means that the valle

Mila [183]

Hi!~

The answer to your question would be micro climate.

Hope this helps!

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4 years ago

The highlighted structure separates the oocyte from the externally located ________. zona pellucida primary follicle corona radi

Naya [18.7K]

Answer:

Granulosa cells

Explanation:

Foliculogenesis is a dynamic and complex process through which the follicle goes through many stages of development in a short period (approximately 60 days in humans and some chimpanzees).

The stages classification is based on morphological changes such as follicular size or diameter, the number of follicular cell layers, etcetera. These classifications might vary among authors but could be denominated as:

Primordial follicle

Primary follicle

Secondary follicle and

De Graaf follicles (This is the one shown in the image)

Through each stage, there are certain modifications in the oocyte, follicular cells, and connective tissue. As the oocyte grows, the follicular cells might reach a size twice or three times bigger than the ones of the primordial follicles. Their shape also changes and they adopt an aspect of stratified epithelium. Their cytoplasm gets a granulous aspect, after what these cells receive the name of granulous cells. The De Graaf follicle characterizes for having a space named follicular antro that displaces the oocyte to one of the sides.

The oocyte at this point gets surrounded by zona pellucida and corona radiata .

The follicular antro (The highlighted structure) separates the oocyte from the externally located granulosa cells or follicular cells.

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3 years ago