What Are Antibodies

question 223

Multiple Choice

What are antibodies?

• A) Connective tissues in the body
• B) Substances in the blood that fight to kill foreign bodies
• C) Mutations that cause the formation of altered DNA
• D) Foreign invaders that stimulate a response from the immune system

---

Definitions:

Chiasma

An X-shaped site in a tetrad usually marking the location where homologous (nonsister) chromatids previously crossed over.

Crossing-Over

A process in which genetic material (DNA) is exchanged between paired, homologous chromosomes.

Haploid Gamete

A reproductive cell, such as a sperm or egg, that contains a single set of chromosomes and thus only one allele for genetic traits.

Prophase I

The first phase of meiosis I, where chromosomes condense, pair up, and exchange segments in a process called crossing-over.