Which is true

Options

A. Centromere is found in animal cells which produces aster during cell division
B. Insulin gene is present in every body cell
C. Nucleosome is formed of nucleotides
D. DNA has a core of eight histones

Answer

To determine which statement is true among the given options, we will analyze each statement one by one.

### Step 1: Analyze the first statement
**Statement:** "Centromere is found in animal cells which produce the ester during cell division."

- The centromere is a region on a chromosome where two sister chromatids are joined together.
- It is present in both animal and plant cells, not just animal cells.
- Therefore, this statement is **incorrect**.

### Step 2: Analyze the second statement
**Statement:** "Insulin genes are present in every body cell."

- Insulin genes are indeed present in every body cell.
- However, these genes are only expressed (turned on) in specific cells, particularly in the beta cells of the pancreas.
- Thus, this statement is **correct**.

### Step 3: Analyze the third statement
**Statement:** "Nucleosome is formed of the nucleotides."

- A nucleosome is a structural unit of a chromosome and is made up of DNA wrapped around a core of histone proteins.
- Nucleotides are the building blocks of DNA, but they do not form nucleosomes directly.
- Therefore, this statement is **incorrect**.

### Step 4: Analyze the fourth statement
**Statement:** "DNA has a core of 8 histones."

- While it is true that nucleosomes contain a core of histone proteins, the statement is misleading.
- A nucleosome consists of DNA wrapped around a histone octamer (which is 8 histone proteins), but it is not accurate to say "DNA has a core of 8 histones" without specifying that this refers to the structure of nucleosomes.
- Therefore, this statement is also **incorrect**.

### Conclusion
After analyzing all the statements, the only true statement is:
**"Insulin genes are present in every body cell."**