In of meiosis, homologous chromosomes pair
up, crossing-over occurs, nuclear envelope breaks down, and a
spindle begins to form.

Prophase I

Explanation:

In prophase I, each pair of homologous chromosomes (one chromosome from each parent) lines up side by side. This aligning of homologous chromosomes is called synapsis. At synapsis, the homologous chromosomes are held tightly together

along their lengths. While they are lined up, segments of the chromosomes may be exchanged. This process of exchange of genetic information is an important mechanism for providing genetic diversity, and is discussed later in this section. As prophase I continues, the centrosomes move to the poles of the cell and the spindle apparatus forms.

c

explanation:

i think

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.