Fill in the blank to complete each statement.

Some species in the weasel family, such as skunks, protect themselves by spraying a foul-smelling musk oil when threatened. Why

Elena L [17]

Before the animal is harmed they spray to keep the predator away

5 0

3 years ago

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What are the two main ways a star can live based on it mass?

Andrej [43]

Answer:

Main sequence stars fuse hydrogen atoms to form helium atoms in their cores. About 90 percent of the stars in the universe, including the sun, are main sequence stars. These stars can range from about a tenth of the mass of the sun to up to 200 times as massive.

Stars start their lives as clouds of dust and gas. Gravity draws these clouds together. A small protostar forms, powered by the collapsing material. Protostars often form in densely packed clouds of gas and can be challenging to detect.

"Nature doesn't form stars in isolation," Mark Morris, of the University of California at Los Angeles (UCLS), said in a statement. "It forms them in clusters, out of natal clouds that collapse under their own gravity."

Smaller bodies — with less than 0.08 the sun's mass — cannot reach the stage of nuclear fusion at their core. Instead, they become brown dwarfs, stars that never ignite. But if the body has sufficient mass, the collapsing gas and dust burns hotter, eventually reaching temperatures sufficient to fuse hydrogen into helium. The star turns on and becomes a main sequence star, powered by hydrogen fusion. Fusion produces an outward pressure that balances with the inward pressure caused by gravity, stabilizing the star.

How long a main sequence star lives depends on how massive it is. A higher-mass star may have more material, but it burns through it faster due to higher core temperatures caused by greater gravitational forces. While the sun will spend about 10 billion years on the main sequence, a star 10 times as massive will stick around for only 20 million years. A red dwarf, which is half as massive as the sun, can last 80 to 100 billion years, which is far longer than the universe's age of 13.8 billion years. (This long lifetime is one reason red dwarfs are considered to be good sources for planets hosting life, because they are stable for such a long time.)

Explanation:

I hope this helped!

3 0

2 years ago

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Directions: Read and understand each question very well. Write the letter on a separate sheet of paper. 1. Which of these explai

tresset_1 [31]

Answer:

1.

1.D

2.D

3C

4.theres no picture so i am not sure what to answer,youre on your own here, just read and research about it on ur module or in the internet, u can do it:D

5.B

6.A

7. the choices arent very clear in what you copy and paste here but the answer is, revolution of the earth around the sun and the earth tilting on its axis or "rotation"

Explanation:

HOPE IT HELPS<3

KEEP LEARNING BUD

5 0

2 years ago

When acetylcholine binds to receptors at the motor end plate, the end plate membrane becames:__________a. repolarized. b. more p

sladkih [1.3K]

Answer:

d. more permeable to sodium ions.

Explanation:

The binding of Acetylcholine with the receptors at motor end plate facilitate membrane permeability to sodium ions therefore opening of voltage gated channels for sodium ions.

Sodium ions diffused into the synapse of post synaptic neuron at the neuromuscular junction.

If the stimulus is up to threshold levels; more chemical(neurotransmitter) gated sodium channels opens, and sodium ions move into the synapse to depolarize the membrane with reversal of charges to generate action potential.

The continuous binding of Acetycholine , leads to permanent opening of sodium ions,and over excitation from depolarization. Acetycholinesterase enzymes breakdown Acetycholine to choline and Acetyl Co -A. These are recycle back to Acetycholiine

7 0

3 years ago

The scientific definition of ______ refers to changes in a species or population over time. systematics genetics evolution biolo

natita [175]

The scientific definition of evolution refers to changes in a species or population over time.

Evolution is a long-term process. It may take millions of years and several generation for an evolution to occur. The cause of evolution can be genetic as well as environmental. The evolution is a result of mutation. Evolution generally gives rise to new species, that is different from its ancestral population.

Population is a group of similar type of organisms. These organisms live in the same habitat, require same resources and have same kind of habits. The most essential criteria that defines a population is that the organisms of a population can mate with each other and produce offspring.

To know more about evolution, here

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4 0

1 year ago

Fill in the blank to complete each statement.​

Fill in the blank to complete each statement.