The chromosomes with equal arms are called ..

The chromosomes with equal arms are called "metacentric" chromosomes. Here are the steps to understand this:

1. Chromosomes are thread-like structures located inside the nucleus of animal and plant cells.

2. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA).

3. Chromosomes are not all alike, they can be distinguished by their length and the location of the centromere. The centromere is the point where two chromatids are attached, and it's also the point of attachment for the spindle fibers during cell division.

4. Based on the position of the centromere, chromosomes can be classified into different types: metacentric, submetacentric, acrocentric, and telocentric.

5. Metacentric chromosomes have the centromere in the middle, so they have two arms of equal length.

So, the chromosomes with equal arms are called metacentric chromosomes.