32. An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to a. make life on land difficult for aerobic organisms. b. change the atmosphere from oxidizing to reducing. c. make it easier to maintain reduced molecules. d. cause iron in ocean water and terrestrial rocks to rust (oxidize). e. prevent the formation of an ozone layer.

d. cause iron in ocean water and terrestrial rocks to rust (oxidize)

Explanation:

The Great Oxygenation Event (GOE) refers to the introduction of huge amounts of free oxygen into the atmosphere. This phenomenon was caused by photosynthetic cyanobacteria during the Paleoproterozoic, i.e., 2.5–2.2 billion years ago. During this period, oxidized iron minerals appeared in the soil and also were deposited on the deep ocean floor due to reactions with oxygen in the seawater from oceans. Moreover, during the Devonian (approximately 410- 360 million years ago), land plants greened the continents and it had brought higher levels of atmospheric oxygen, thereby increasing the amount of oxidized iron in the soil and rocks.

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.

i believe it would be c: tons.