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At rest a nerve cell or fiber has more sodium (NA+) ions in the extracellular fluid and more potassium (K+) ions in the intracellular fluid. There are both NA+ and K+ ion channels in the membrane of the n...

Of course. Spermatogenesis takes place in the seminiferous tubules of the testis. The germinal epithelium cells, which are in the wall of the seminiferous tubule, first differentiate into diploid spermato...

Similarities Nucleotides consist of pentose sugar, phosphate and base

Differences RNA: ribose (sugar) single stranded Made in the nucleus but can move outside it U, A, G, C bases

DNA: deoxyr...

Allopatric speciation occurs when populations of a species are separated by a physical barrier - this could be a river for animals that cannot swim, for example. Separation of the populations means that t...

DNA (deoxyribonucleic acid) is a double helix composed of units called nucleotides. Each nucleotide is composed of a single deoxyribose sugar, a phosphate group and one of four nitrogen bases. The 4 bases...