This type of cells can develop into many different kinds of cells in the body.
Scientists hope ______ can be used to repair damaged organs in the future.
stem cells
This nutrient provides energy, but eating too much of it may increase cholesterol.
Although our bodies need some ______ for energy, eating too much can be unhealthy.
fat
This long-term rise in Earth's average temperature is mainly caused by greenhouse gases.
Many scientists agree that ______ is causing sea levels to rise.
global warming
This adjective means "morally right or acceptable."
Many people believe it is not ______ to test cosmetics on animals.
ethical
This verb means "to use something such as food, water, or energy."
People should not ______ more water than they need.
consume
This is the earliest stage of development of a human or animal before birth.
A human ______ develops into a baby before birth.
embryo
This type of substance can be harmful or poisonous.
Some cleaning products are ______, so children should not touch them.
toxic
This phrase refers to long-term changes in Earth's weather patterns.
Governments are introducing new policies to slow down ______.
climate change
This noun refers to the stage of human society with advanced culture and organization.
Many people believe that in an advanced __________, killing animals for their meat is a rather cruel act.
civilization
This noun means "the use of something, especially food, energy, or products."
Reducing energy ______ can help protect the environment.
consumption
These body parts contract and relax to help us move.
Regular exercise strengthens your ______ and helps you stay fit.
muscles
This verb means "to put a liquid or medicine into the body using a needle."
The nurse had to ______ the patient with the medicine.
inject
This noun means something useful that people or countries can use, such as water or oil.
Fresh water is one of the world's most important natural ______.
resource
This noun refers to being aware of yourself and the world around you.
Doctors still do not fully understand human ______.
consciousness
This adjective describes something made by people rather than occurring naturally.
Many sports fields today use ______ grass instead of real grass.
artificial
This noun refers to a group of similar cells working together to perform a function.
Human skin is made up of different kinds of ______.
tissue
This verb means "to remove something from a larger whole."
Scientists can ______ DNA from a person's hair.
extract
This adjective describes something that is dangerous or likely to cause harm.
Workers must wear protective clothing when handling ______ chemicals.
hazardous
This verb means "to produce offspring or create more of the same kind."
Most animals must ______ in order for their species to survive.
reproduce
This noun has two meanings: an answer to a problem or a liquid in which substances are mixed.
After several hours of discussion, the team finally found a ______ to the problem.
solution
This verb means "to increase in number rapidly."
Bacteria can ______ very quickly in warm conditions.
multiply
This verb means "to grow animals or children until they become adults."
Her grandparents ______ sheep on their farm in the countryside.
raise
This verb means "to find the answer to a mathematical problem or work out an amount."
Can you ______ how much the trip will cost?
calculate
This adjective describes something intended to be sold or used in business.
The company plans to produce the product on a ______ scale next year.
commercial
This word means "to use food, energy, or resources."
We need to ______ less electricity if we want to reduce our bills.
consume