The sebaceous and sweat glands associated with the skin are classified as glands because they release secretions to the skin's surface via ducts.

exocrine glands

Explanation: Exocrine gland secrete substances to an epithelial surface through a channel.

The sebaceous and sweat glands associated with the skin also secrete substance to skin surfaces via ducts/ channels and are classified as endocrine gland. There are two glands in the human body Exocrine gland and Endocrine gland.

Endocrine gland secrete substance into the bloodstream directly. Examples of exocrine glands are sweat, salivary, mammary, sebaceous, and mucous.

liver and pancreas are both exocrine and endocrine glands simultaneously.

As exocrine gland, the liver secrete bile and the pancrease secrete pancreatic juice into the gastrointestinal tract through channels. While as endocrine gland they secrete other substances directly into the bloodstream.

rain is the best answer

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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