B. animals
Plants have cell walls, bacteria are unicellular and fungi have cell walls too
Answer:
Lysine
Explanation:
lysine residues on the histone tails of the octamer cn be activated by both acetylation and methylation patterns to influence accessibility or silencing of the genes respectiviely. for example, acetylation of H3K27 (histone 3 lysine residue 27) brings about a region of active chromatin allowing access to transcription activity while its trimethylation will cause silencing of the associated gene at that particular area (no expression of that gene)
Answer:
Because natural selection selects for it. Thus it persists.
Explanation:
You have to understand heterozygote advantage. Basically, it's where heterozygotes have an advantage over homozygotes. In the case of sickle cell disease, heterozygotes have an advantage, and natural selection favors whatever is advantageous. Thus, because heterozygotes each have one recessive sickle-cell allele, as natural selection favors the heterozygotes, the recessive sickle-cell allele persists and remains in the gene pool.
