The heavier elements on the earth (those with atomic numbers greater than 5) choose one: a. were formed immediately after the big bang. b. were in existence at the moment of the big bang. c. are constantly being created by fusion in our sun and blown here by the solar wind. d. are formed by stellar nucleosynthesis during the life cycles of existing stars.

Option D,  are formed by stellar nucleosynthesis during the life cycles of existing stars.

Explanation:

The light weight elements such as hydrogen, helium, lithium etc were formed during the Big Bang nucleosynthesis.  

Later on  further evolutions started in stellar object and stars that were heavier than sun underwent reactions in succesive stages of stellar evolution that converted light weight elements such as helium into carbon and oxygen. However, in more massive stars , elements like silicon and iron were produced.  

Hence, option D is correct

answer: although many types of viruses can cause a common cold, rhinoviruses are the most common culprit. a cold virus enters your body through your mouth, eyes or nose. the virus can spread through droplets in the air when someone who is sick coughs, sneezes or talks. theres your answer

explanation:

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.