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2 years ago

What's responsible for preventing the gas giants from collapsing into a star?

Biology

2 answers:

Tasya [4]2 years ago

8 0

Answer:

They spin very quickly on their axes.

Explanation:

The gas giants spin very quickly, creating a strong centrifugal force. This strong centrifugal force prevents them from collapsing under gravity.

olchik [2.2K]2 years ago

4 0

Gas giants do not have enough mass that holds much gravitation force to ensure collapsing into a star. The gravitation pull is not strong enough to cause the fusion of hydrogen atoms. These gas giants, such as Jupiter, therefore, do not become stars.

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The phloem tissue of vascular plants is primarily composed of sieve elements and companion cells. These components allow the tis

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I believe the answer to the multiple choice is c I’m not to sure

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2 years ago

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The ancient remains of plants preserved in the earth in the form of coal, oil, and natural gas are called

goldfiish [28.3K]

The remains of plants and animals preserved in the earth => fossils
coal, oil, natural gas => fuels

fossil fuels

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2 years ago

When acetylcholinesterase outlasts the release of acetylcholine from the synaptic vesicles, the skeletal muscle __________?

IceJOKER [234]

Answer:

relaxes

Explanation:

Acetylcholine is the substance responsible for the transmission of nerve impulses from pre-postganglionic neurons, in the ganglia of the autonomic nervous system. At the level of the parasympathetic nervous system, the transmission between the postganglionic neuron and the effector organ also mediates. In addition, it is the mediator of the nerve transmission of the terminal motor plate.

There are large differences in the effects that Acetylcholine triggers at different cholinergic transmission sites

Intra-arterial injection near Acetylcholine produces muscle contraction similar to that caused by motor nerve stimulation. Decreased resting potential in isolated intestinal muscle and increased frequency of spike production, accompanied by increased tension. In the cardiac conduction system, nodes S-A and A-V, it produces inhibition and hyperpolarization of the fiber membrane; and pronounced decrease in depolarization speed. Central regulation of extrapyramidal motor function. Exciting effect of the basal ganglia that counteracts the inhibitory action of Dopamine. Although cholinergic innervation of blood vessels is limited, cholinergic muscarinic receptors occur in sympathetic vasoconstrictor nerves. The vasodilator effect on isolated blood vessels requires the presence of an intact endothelium. The activation of muscarinic receptors causes the release of a vasodilator substance - relaxing factor derived from the endothelium - that diffuses to the smooth muscle producing relaxation.

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2 years ago

Drag each tile to the correct box. Explain the process in which hormones secreted by the pancreas function with respect to incre

olga55 [171]

Answer:

The correct order is:

High amount of glucose in the blood, sending signals toward the pancreas.
Synthesis of hormones by beta cells.
Binding of hormones with receptors on the liver.
Intake of glucose molecules from the blood by specific transporters.
Release of hormones from the receptors

Explanation:

The pancreas produces two hormones important for the regulation of blood glucose levels.
The two hormones, glucagon and insulin, increase and decrease the blood sugar respectively.
Insulin lowers the blood glucose by stimulating the body cells to increase the intake of glucose.
The brain senses high/low blood glucose, then, sends signals to the pancreas to initiate the synthesis of insulin or glucagon by the beta cells.
These hormones bind to receptors on body cells; on hepatic cells, in case of insulin.
The receptors initiate cellular signaling that facilitates intake or exit of glucose in or out of body cells.

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2 years ago

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6. In fossils, what anatomical evidence indicates that gills were present?

Phoenix [80]

Answer and explanation:

6. In fossils, what anatomical evidence indicates that gills were present?

The anatomical evidence found in the fossils, such as special bone structures in the shoulders and skulls to support the gills, allows us to know the existence of these structures in some ancient species.

7. Many transitional species had gills, which means they lived in aquatic environments.

Gills are structures which allow people to breathe underwater, and many evolutionary transition species had them, such as the Tiktaalik, which also had lungs.

The existence of gill and lung respiration is what leads us to think that transition species were the first to leave the aquatic habitat to become terrestrial tetrapods.

8. Lungs allow an animal to breathe air. Why did this adaptation evolve?

Species considered transitional between fish and land animals were equipped with both gills and lungs.

It is suggested that the appearance of the lungs is due to the lower concentration of oxygen in the water and the need to obtain oxygen from another source, such as air, where the oxygen concentration is higher. In these circumstances, increased oxygen demand forced some animals to leave the aquatic habitat.

9. Tetrapods use lungs to breathe. Do any modern tetrapods have gills? Explain.

Some present-day tetrapods - such as salamanders, toads and frogs - are amphibians, and in their larval stage they remain in an aquatic habitat, so they are equipped with gills during this stage of their life cycle.

In amphibians like the frog, the passage from the larval stage to the adult stage involves a process called metamorphosis, in which the gills disappear and the lungs develop, in addition to the appearance of the four limbs, which are absent in the larva.

13. Most modern tetrapods have five digits on front limbs and five digits on back limbs, although some species have fewer. How does this number compare to the number of digits on the limbs of transitional fossil forms?

The transitional species originally had fins, but fossils of the first tetrapods have been found with developed limbs and five or more digits, representing an equal or greater number of digits than current species.

An example of a larger number of toes is represented by the genus Acanthostega, with eight toes on each limb.

14. Why do many of the transitional fossils between fish and tetrapods have flat heads?

Many of the transition fossils between fish and tetrapods have flat heads, from top to bottom, because these species participated in the transition between aquatic and terrestrial habitat, adapted to living in shallower waters near the surface, and with gill and lung breathing capacity.

15. How did the anatomy of the shoulder and head change during tetrapod evolution?

The changes in the anatomy of the shoulder and head during the evolution of the tetrapod were basically three:

The bony skeleton of the shoulder is separated from the skull, which in aquatic animals was attached.
The appearance of the neck, between both structures.
Development of an independent movement of the skull, with respect to the shoulder and the rest of the body.

16. Tiktaalik and Acanthostega are fossil species have characteristics unique to fish as well as characteristics found in fish and tetrapods. Describe the characteristics of lobe-finned fish that are similar to those of tetrapods.

Lobe-finned fish -called sarcopterygians- like dipnoi, are lungfish, given the existence of functional lungs in their body. Another characteristic of lobefish is that each of their fins is attached to a single bone, as in the case of the humerus and femur of mammals.

The existence of lungs and the attachment of the limbs to a bone are common features among lobed finfish and tetrapods.

17. Which lobe-finned fish is alive today?

The coelacanth is one of the oldest species of fish that exist, as they are lobe-finned fish that were thought to be extinct, but still exist.

The characteristic of possessing lungs and bony skeleton relates them to the actual lung fishes and to the terrestrial vertebrates.

18. Acanthostega and Icythyostega have been called fish-like tetrapods. Explain why they are described as such and describe the environment in which they probably lived.

Both the Acanthostega and the Icythyostega were animals characterized by having four extremities and be equipped with gills and lungs at the same time, which determines that they are called tetrapods similar to fish.

Their characteristics made them suitable for living in aquatic and terrestrial environments, so they probably inhabited shallow waters or even the surface of the earth.

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2 years ago