3. Read these sentences from the article. "I've often wished that I had a time machine to go back and collect a sample of ancient
atmosphere or an ancient bit of seawater," says (Jay] Kaufman. "But we can't. All we
can do is collect rocks that were formed under those waters and under that
atmosphere."
Which conclusion does this statement support?
A. Scientists are skeptical about their ability to determine when oxygen levels in the
Earth's early atmosphere rose.
B. Scientists are unable to study what the Earth was like millions of years ago because
they do not have the materials needed to do so.
C. Scientists study the atmosphere in order to learn what the Earth's seawater was like
millions of years ago.
D. Scientists study rock formations in order to learn what Earth's atmosphere was like
millions of years ago.

you are the source of the heat energy. you can minimize the heat energy by selecting the appropriate clothes to wear.

i dont know this but ask your teacher for !

the answer to your question is:

c. complementary base-pairing

question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.