Question

question 3
which statement best explains why nerve and muscle cells can be so differ
they have different numbers of mitochondria
these cells express different genes
these cells have different environments
only one of these cells have histones
question 4
what differences in dna methylation would you expect to see in a 103 year-
methylation increases with age
methylation moves up and down throughout life

Explanation:

1. For Question 3: All somatic cells share identical DNA; cell specialization (nerve vs. muscle) arises from differential gene expression, where distinct subsets of genes are activated to produce cell-specific structures and functions. The other options are incorrect: mitochondria count is a functional adaptation, not the root cause of cell difference; cells share the same body environment; all eukaryotic cells have histones.
2. For Question 4: Epigenetic research shows that global DNA methylation generally increases with age, which is linked to age-related gene regulation changes and cellular aging processes. The option of methylation fluctuating randomly does not align with consistent age-related methylation trends.

Answer:

1. Question 3: These cells express different genes
2. Question 4: Methylation increases with age