Answer:
A. Lancelet
B. All chordates
Explanation:
A. Dorsal nerve chord is the only <u>unique feature</u> among all members of <u>phylum chordata</u> (mainly found in subphylum Vertebrata). In the given list, only lacelet is the Chordate whereas <u>snail belongs to phylum Mollusca</u>, <u>grasshopper belongs to Arthropda</u>, and <u>jellyfish belongs to Cnidaria</u>. Dorsal nerve cord runs along the length of organism's body.
B. <u>Gill slits</u> are <u>opening structures</u> to gills through which water passes from pharynx/throat to exterior. Their main purpose is to help filter the food particles available in surrounding water. Although they are typical for amphibians and fishes, chordates also possess gill slits at embryonic stages.
Subtract the atomic number from the atomic mass to get the neutrons
Endocrine signaling is hormone based signaling that travels through the blood stream. Many of the sensors and integrating sensors of the endocrine system are located in the brain. The brain barrier contributes to endocrine signalling, such that the brain barrier does not factor in with endocrine signalling. The answer is A
Identifying the genetic sex of a child is based on finding intracellular Barr bodies that consist of inactive chromatin material.
Inactive chromatin material is the one where no transcription takes place. It is also known by the name heterochromatin. It appears as a dark condensed form in the chromatin.
Barr bodies are the inactive X chromosomes. These are mad inactive by a process termed as lyonization. It is essential to make the chromosome inactive in organisms with XY type of sex determination. They are present at the periphery of the nucleus. Inactivation of X chromosome makes the amount of X chromosomes equal in both, males and females.
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