Which statement is true? Membrane phospholipids always comprise the majority (by weight %) of a cell membrane. The fluid mosaic model considers biological membranes to be a sea of lipids floating in the aqueous fluid of the cytoplasm. All membranes in a given cell have the same lipid composition. Lipid bilayers are essentially impermeable to polar solutes.

lipid bilayer are essentially impermeable to polar solutes

Explanation:the cell membrane is a phospholipid bilayer.it is composed of lipids,proteins and carbonhydrates attached.the lipid bilayer forms the bulk of material on the membrane as a result it is impermeable to the movement of polar molecules in and out of the cell.small and non polar substances can pass through the bilayer of the membrane. the lipids and proteins occurs in varying composition in the membrane, depending on the

cell .the membrane has both a hydrophobic end and a hydrophilic end.the hydrophobic ends of the membrane folds toward each other.while the hydrophilic end is exposed to the water phase.the membrane is very flexible and thin and acts as a barrier that separates the cells external and internal environment

Lipid bilayers are essentially impermeable to polar solutes.

Explanation:

The lipid bilayer is a thin polar membrane made up of two layers of lipids,  proteins and carbonhydrates, these membranes are flat sheets that form a continuous barrier around cells and their structures. It is the barrier that keeps ions, proteins and other molecules where they are needed, preventing their dispersion. It is impermeable to the movement of polar molecules in and out of the cell, where small and non polar substances can pass through the bilayer of the membrane.

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.

answer: grassland biomes are closer to the equator and receive more rain.

grasslands are biomes that are dominated by grasses rather shrubs and trees. savanna are biomes that exhibit grasses, shrubs and small tree as vegetation. grasslands are located near the equator of the earth. these are found in north america. savanna biomes are found in africa, south america, australia and india. grassland exhibit moderate climatic conditions, it receives   amount of rainfall higher than savanna.   therefore, savanna exhibit dry and hot climatic conditions.