Answer:
The correct option is A. they evolved from land mammals.
Explanation:
Evolution can be described as a process through which organisms in a species change over a period of time due to the natural selection of the environment. Those organisms that have many similarities in their functions or structures are considered closer to one another and have the same common ancestors.
The properties mentioned in the question about cetaceans resembles the properties of land mammals. For example, cetaceans lack gills and breathe air. Land mammals also do not have gills and need to respire for living. The cetaceans have fin bones which are similar to the limb bones in the land mammals. Hence, these observations show that cetaceas have evolved from land mammals.
Answer:
A cell wall
Explanation:
Plant cells are enclosed by a rigid cell wall. When the plant cell is placed in a hypotonic solution , it takes up water by osmosis and starts to swell, but the cell wall prevents it from bursting.
Answer:
Proteins seem better suited for storing genetic information because DNA is only made from 4 bases while proteins were made from 20 amino acids, Scientists thought that proteins could code for much greater variety in their amino acid sequence than DNA could in its nucleotide sequence.
Answer:
4. Thyroid hormone levels decrease, TRH level increase, PRL level increase
Explanation:
Surgical removal of Thyroid gland will lead to hypothyroidism.
Normally, the surgery is followed by maintenance dose of thyroxine to avoid side effects.
In the presence of hypothyroidism, however, the decreased thyroid hormone will lead to increase in thyrotropin releasing hormone (TRH). increased TRH increases production of prolactin. (but less than that in prolactinoma)
Hello
It is because ur mouth is a dark and warm place which is the perfect environment for bacteria to grow and survive. It doesn’t matter if u brush it really well on ur tounge there and groves in ur tounge where the toothbrush bristles cannot reach and clean so that is where the bacteria lives.
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