The mass number of carbon-12 is twelve as it contains 6 neutrons and 6 protons. Likewise, carbon-13 isotope contains 7 neutrons and 6 protons, while carbon-14 isotope contains 8 neutrons and 6 protons.
Answer:
False
Explanation:
The blood brain barrier (BBB) is a selective border that prevents the entry of foreign substances into the brain. It is made up of different components including endothelial cells, astrocytes, and pericytes etc.
Of all these mentioned three, the endothelial cells are directly responsible for the selectivity of the BBB. The endothelial cells are bound together by the tight junctions situated between them, impeding the passage of foreign materials e.g. solutes, pathogens etc.
Astrocytes help to maintain the BBB by surrounding the endothelial cells, providing biochemical strength.
The pericytes are located in the basement membrane, where they communicate with endothelial cells. They help to sustain the BBB by stabilizing and monitoring the maturation of endothelial cells via communicating directly between cell membrane as well as paracrine signalling.
Answer:
- They have dorsal nerve chord.
- They have pair gilled pouches.
- They breathe through gills.
- They have a notochord.
- They are coelomate.
Explanation:
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Brainliest would be nice
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