In the atmosphere, a reduction in carbon dioxide will result（）.
Global temperature rising
Precipitation reduction
Precipitation increase
Temperature dropped
In general, the amount of water in vegetables( ).
The disk is painted in seven colors. If you rotate the disk quickly, what color do you see( ).
Which country is the pyramid in（）?
India
Brazil
Pakistan
Egypt
What is the proportion of oxygen in the air（）?
How many bones are there in the human body（）?
The first time an American walked on the moon was in ().
What should be used for indoor dehumidification （）？
activated carbon
slaked lime
refrigerator
cooler air-conditioner
The light wave used to disinfect is( ).
infrared radiation
Ultraviolet
Laser
X-ray
Which of the following foods should be avoided for colds ？
marine fish
soybean milk
green vegetables
ginger
The shelf life of food refers to its:
Production date
Final consumption period
Best consumption period
Manufacture date
The remedy for a person's swollen body due to malnutrition is（）.
Eat more vegetables
Drink lots of bean juice
Eat more steamed bread
Drink more water
The 20th century produced many revolutionary technologies, the greatest of which was ().
Movie
TV
Computer
Internet
Lobster is one of our delicacies. What color is the blood in its body?
One nanometer is one meter (), which is about the length of 45 atoms arranged together.
one hundred thousandth
one millionth
one billionth
() is a kind of marine energy power generation, but it is the earliest development, the largest scale and the more mature technology in the utilization of marine energy.
tidal power generation
wave power generation
tidal power generation
In early 2004, NASA's two Mars rovers landed successfully. Which of the following is not included? ()
courage
opportunity
mariner
Weigh one's own body at the equator and go to the North Pole again under the same physical conditions ()
equatorial heavy, Arctic light
equatorial light, Arctic heavy
is the same weight
A balloon filled with gas. Let it go. It will: ().When it reaches a certain height, it stops rising
keeps going up
When it reaches a certain height, it stops rising
one straight up, the final explosion
Generally speaking, the environment is quiet when the sound is below ().
In a room with constant temperature, it's colder to stand barefoot on tile than on cotton because: ().
cotton temperature is higher
ceramic tile heat conduction is faster
The illusion of the body
The reason why incandescent lamps turn black after being used for a long time is that:().
glass aging
glass changes color when heated
tungsten wire evaporation
The "queen bee" and "worker bee" are:()
female bee, male peak
female bee, female bee
male peak, male peak
male peak, female bee
The main functions of grooves on automobile tires are as follows:
increase friction with the ground
remove rainwater and mud
increase body cushioning
Of the following statements about the relationship between force and motion, which one is right:
A body cannot move without an external force, which is a reflection of Newtons first law
The greater the force on a body, the faster it moves, which is in line with Newtons second law
When the external force on the object is 0, the velocity must be 0. When the external force on a body is not zero, its velocity must not be zero either
When the force applied to the object is very large, its velocity can be 0; When the resultant force on the object is 0, the velocity can be very high
If an object falls freely from a certain height, it passes through 1/4 of the whole journey in the first second. How long does it have to fall before it falls to the ground?
The Tindal effect is observed when a beam of light passes through the following dispersed system：
KCl solution
Fe (OH) 3 Colloid
Sucrose solution
KNO3 solution
In the following statements about NO, which one is true
Red-brown gas
Can be collected by exhaust air method
Can be collected by means of drainage
Less dense than air under the same conditions
Which of the following actions do not meet safety requirements:
Discard the remaining sodium metal in the waste paper basket
If a small amount of alcohol is spilled on the table, put it out immediately with a damp cloth
To smell the gas, gently flap your hand so that a small amount of the gas wafts into your nostrils
When dilute the concentrated sulfuric acid, slowly inject the concentrated sulfuric acid into the water along the wall of the device and keep stirring
The sample analysis of a biological small molecule found that it contains C, H, O, N, P and other elements, which may be：
Amino acids
Nucleic acids
Crystalline bovine insulin
Deoxynucleotide
If the average molecular weight of the amino acids that make up a protein is 130, then the molecular weight of a protein consisting of four peptide chains totaling 280 amino acids is:
Farmers dry the seeds after harvesting rice and soak them before sowing them, mainly because
Free water content affects metabolism
Bound water is an important component of cells
Water is an important raw material for photosynthesis.
Water is an important raw material for respiration
How do snakes go forward? ()
By feet
By abdomen
By squama
By legs
What’s the purpose of glowworm shining? ()
To courtship
To alert
To trap their food
All of above
How many muscles are in humans’ body? ()
nearly 500 pieces
nearly 600 pieces
nearly 700 pieces
nearly 800 pieces
What’s the largest mammals in the whole world?
Sulphur-bottom
Shark
Gorilla
Elephant
Which kind of tree has the longest history in the world?
Gingko
Birch
Eucalyptus
Mulberry
There's a bottle of air, take out half a bottle, is there half a bottle left?
Is a sundial a measure of length?
Can light be refracted when it enters water from air?
Periscope is made using the principle of refraction of light.
Water absorbs heat and dissipates heat faster than sand.
Can water vapor be turned into ice by direct cooling?
When the body is still, the muscles are also still.
The bubbles you blow with soapy water must have color?
Does gas expand and contract in heat and in cold?
The first discipline to appear in the natural sciences was mathematics.
The astronomer who discovered the laws of planetary motion was Copernicus.
A nano is a unit of length.
Electric energy is one of the most widely used energy sources, and it belongs to primary energy.
In the 1960s, the first humans to reach the moon were the Soviets.
The nine planets from near to far from the sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
The plum rain in south China belongs to frontal rain.
The most massive of the nine planets is Neptune.
The first to develop an atomic bomb was the Soviet Union.
In 1876, Marconi, a Scot living in America, experimented with the wired telephone.
Animals with low blood temperatures are cold-blooded.
The national bird of France is the rooster.
Green tea is a fermented tea.
Animation originated in Japan.
Fish can also infect parasitic diseases and skin diseases.
The swimming temperature in life is about 33 degrees.
Compass is a kind of instrument for indicating direction by using the North-South polarity of magnet.
Forest is also called "factory" and "barrier".
The moon is the planet of the earth.
The first inert gas found in the air is neon.
Antarctica is the largest ice area in the world.
The average radius of the earth is 63710km.
The woodpecker is a famous forest surgeon.
The most sensitive olfactory animal is the dog, which has 2.2 billion olfactory cells.
The fastest animal is the Amur tiger.
Mammals have the longest life span.
The tree with the most oil content is oil palm, known as the "king of oil in the world".
The origin of peanut is the United States.
The oldest tree in history is ginkgo biloba, known as a fossil of the sea.
The decline of melanin makes our hair become white.
Rabbits delivery information by hitting the ground with their legs.
The Big Bang happened ten billion years ago.
Hot air is heavier than cold air.
The sky is blue because the blue light has the strongest penetrating power.