Answer:
d) polyps; calcium carbonate
Explanation:
The Acanthaster planci It is a kind of invasive starfish, which destroys corals: it has poisonous spines and feeds on coral polyps at the expense of the reef.
On the other hand, CO2 reacts with water, forming carbonic acid and reducing the available calcium carbonate, an essential element so that marine organisms, from clams to hedgehogs, can form their skeletons and shells.
Answer:
I would say that meat is more energy efficient than vegetables because meat have more calories than vegetables do. Calories equal energy. For example, vegetables have an average calorie of 10 - 90 calories. While meat has 100 - 1200 calories. So, if calorie equals energy, I would say that calories are the reason why meat has more energy in it.
Explanation:
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Answer:
The ability of sequences within the leader mRNA to pair with one another and form stem-lopp structures
Explanation:
A form of feedback regulation controls the trp operon by regulating transcription termination, a mechanism referred to as Attenuation.
-In the presence of high concentrations of tryptophan, RNA polymerase ceases transcription shortly after initiation in a region called the leader sequence.
-If the concentration of tryptophan is low, transcription does not terminate until the entire operon is transcribed. The mechanism of attenuation links alternative RNA secondary structures to transcription termination.
-Immediately after transcription, RNA from the leader region folds into one of two alternative secondary structures.
-One of these structures is a transcription termination signal that stops RNA polymerase from continuing to the end of the operon.
-The alternative structure does not contain a transcription termination signal and allows transcription of a single mRNA that encodes all the structural genes.
-The decision as to which of the two alternative RNA structures formed is regulated by the concentration of tryptophan.
Compared to arteries, valves have no pulse, have thin walls and have valves that prevent backflow of the blood. The pressure in the veins is less than that of the arteries, hence, there is no pulse. They are nearer to the surface of the skin. It also connects arteries and capillaries which transport blood all throughout the circulatory system.
Answer:
correct option is A.
Succession is the process by which the structure of a particular community evolves over a specific period of time. There are two types of succession, primary and secondary succession. Primary succession is a type of succession that occurs in a place which is incapable of sustaining the growth of plants, that is, it usually occur on barren lands. All the options given above are examples of places for primary succession with the exception of option A.