In the fluid-mosaic model of the plasma membrane, the phospholipid molecules are oriented so that the heads are facing the outside environment and the tails are facing the interior of the membrane.

Hydrophilic heads facing exterior

Hydrophobic tails facing interior

Explanation:

In 1972, the fluid mosaic model was proposed to describe the structure of the plasma membrane. This model describes the plasma membrane to possess components including phospholipids, cholesterol and proteins. The phospholipid component is composed of glycerol, two fatty acids and a phosphate-containing head, which are arranged in two adjacent layers forming the phospholipid bilayer in the membrane of biological organisms.

Phospholipids have both the hydrophilic and hydrophobic region. Hence they are said to be AMPHIPATHIC.

The head of the phospholipid is negatively charged due to its phosphate content, making it polar and hydrophilic i.e. water-loving. This hydrophilic head faces the exterior of the cell in order to interact with fluids.

The tails of the phospholipid are long fatty acids that keep away from water i.e. hydrophobic. Due to their water-fearing nature, they avoid water and face the interior of the cell, where each tail face each other.

d concave shape of wave rock

explanation:

the concave shape of wave rock is a very good evidence that supports the evolution of earth due to chemical weathering. if we talk about structure of   wave rock, studies have estimated that it is around 2.7 billion years old. it also serves as the foundation of evidence that it was the place where australian continent began to form.

how the structure of wave rock was created?

studies suggest that structure of wave rock was created when the surrounded area was started to weather due to which deposition of material started on the part of land which now contains wave rock.

the structure of wave rock is considered to be one of the best-known landforms in australia. at the height of around 15 cm, there can be found flared slopes which formulate the margins of hyden rock. it is now assumed by geologists that wave rock was created by subsurface water-induced weathering and not by glaciers, waves or wind.

due to deposition of material over the period of long time, the wave rock became tougher and tougher due to weathering from surrounding terrain. this makes it a physical evidence that supports   the evolution of earth due to chemical weathering.

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some of your causes might be acidic rain or natural wildfires that cause the parks to be degraded

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