Science quiz questions, science questions. Detailed answers.

The arterial pressure is too high to enter, the artery is deeper than the vein, it is not easy to find, and the artery is more dangerous.

First, oxygen enters the bloodstream through the alveoli and binds to hemoglobin, where it is transported to various parts of the body to participate in metabolism.

Food is digested and absorbed into sugar, fat, etc., which are stored in the liver and fat cells, and released when needed to participate in metabolism.

The chemicals and smoke particles produced after tobacco combustion have adverse effects on the lungs and other organs, reduce resistance, increase the chance of tumors, and also harm the nervous system, especially the brain.

1 Entering an artery can interfere with normal oxygen delivery. Moreover, the arterial blood flow velocity is large and easy to overflow, so you must know that arterial bleeding can kill people.

2. Oxygen is combined with hemoglobin, and nutrients such as sugars, lipids, and proteins in food are broken down into small molecules such as glucose, amino acids, and glycerol, which are entered by capillaries and circulated throughout the body.

3. The eye contains nicotine and other drugs, which are easy to produce chemical carcinogenesis; In addition, it contains a small amount of radioactive substances, which can easily cause physical carcinogenesis to humans.

Summary. Okay have received your **.

Okay have received your **.

I'll take a look first.

Problem 1: Small.

Problem 2: Big.

Okay received your**.

27.Compared with the two pictures in the material, Figure A is better, because the material shows that the temperature of the external flame of the alcohol lamp is better, and Figure A is cautious about this, and Figure A and Figure B are compared with Figure A, Figure A has a heat shield and Figure B is directly heated, if direct heating will cause the heated object to produce different wheel shirt reactions. So the wide tung cover said that the nail picture is better.

26.The sea wave in the inner layer of the isolation layer gradually increases according to the different heating temperatures, and finally changes to 50 degrees Celsius with the heating time, while the water in the thermos cup gradually decreases with the decrease of the temperature.

1.The buoyancy experienced by the copper ball is the weight of water equal to the volume of the copper ball.

2.As the pellets are immersed in water, the pressure of the water on the bottom of the bucket increases. Because the copper ball is immersed in water, the liquid level of the water surface rises, that is, the liquid column above the bottom of the barrel increases, so the pressure at the bottom of the barrel increases.

3.The number of spring scales is increased. The increased value is equal to the buoyancy experienced by the copper ball.

1.A machine consisting of a round wheel and an axle like a steering wheel is called an axle.

2.Using a ramp to lift a heavy object is a simple way to lift a heavy object that we commonly use. This ramp is also a simple machine, called ( slope ).

3.The structure of the bicycle is divided into four parts: (wheel), (sprocket), (chain), (car frame). Wish.

Roots: roots, strawberries, ginger.

Leaves: aloe vera, spider plant, jujube, Lu Yuan,

Stems: potato, sweet potato, tulip stool, poplar, moonflower, chrysanthemum, seeds: carrot, creeper,

Evergreen, gems are not known to Qi Hua.

Propagated with roots are: carrots, potatoes, sweet potatoes, dandelions, poplars, and trees

There are poplars, aloe vera, creepers, Liang Bi evergreen, spider plants, and tulips.

The ones that are propagated by stems are: jewel flower, moon flower, chrysanthemum, strawberry, ginger.

The speed of sound is 340 meters per second and the speed of light = 300,000 kilometers per second.

Audience t1 = 30 340 = 3 34

Shanghai's t2 = 1460 300,000 =

Obviously, T2 is relatively small, and Shanghai's first to hear it.

This is too pediatric, right?

The speed of light is 300,000 kilometers per second, and the speed of sound is 347 meters and seconds.

347 30 = about seconds, 1460 300,000 = about seconds.

Obviously, it was the audience in Shanghai who heard the sound first.

Big brother, do you think sound can travel directly at the speed of light? There must be intermediate equipment to convert the acoustic signal into an electrical signal or other signals to transmit, and it depends on the position of the on-site signal receiver, signal processing speed, etcIf you don't want to count, then you think it's the first to hear it.

30 is divided by the speed of sound, and 146 is divided by the speed of light, so the Shanghai audience hears it first, but in fact, the audience hears it first. Because the process of arriving in Shanghai is complicated, it needs to go through steps such as modulation and demodulation.

30 340= seconds.

1,460,000 (3 10 8) = seconds.

Less than means that Shanghai hears Shanghai first.