Answer: Option A
Explanation:
A tunicate is marine invertebrate animal which is a part of chordates. They have notochords and dorsal nerve chord. The subphylum of the organism is called as Urochordata.
The adult urochordates lack notochord but the larval stage of the urochordates have notochord. This is because it helps in swimming of the organism which is required only at the larval stage.
The adult stage of the tunicates is sessile and they do not swim so they do not require notochord.
The<span> duodenum is the first segment of the small intestine</span>
The structure of DNA is double helix which looks like twisted ladder. The sides of the DNA molecule, the rails of the ladder are composed of alternate phosphate and sugar molecules.
<span>The hypothesis has to survive all attacks on it and continue to provide the best known explanation of the known data.
In the scientific method, there are several steps towards the creation of a hypothesis and eventually a theory.
1. Gather data.
2. Construct a hypothesis that explains the data. This hypothesis should be capable of being disproved and should be capable of making predictions.
3. Gather more data. DO NOT cherry pick only that data which supports the hypothesis . If data is uncovered that contradicts the hypothesis , revise or replace the hypothesis.
4. After the hypothesis has survived all attacks on it and is the best known explanation of the data, then it becomes a theory.
5. Note, data collection continues after the hypothesis became a theory and if new data is discovered that is in conflict with the theory, then the theory is modified, or discarded in favor of a new hypothesis or theory.</span>
Answer:
the answer is c- the cell theory describes the natural world
