The crossing of individuals of the same species with different genetic characters is

Step 1: Analyze the question The question asks for the term describing the mating of individuals of the same species that have different genetic characters (different genotypes or traits).

Step 2: Explain the concepts

• Cross breeding (outbreeding): mating between genetically different individuals of the same species (or sometimes different varieties or breeds). It increases genetic variation and can produce hybrid vigour. Example: crossing a tall pea plant with a dwarf one, or crossing two different breeds of cattle.
• Polygenic inheritance: a single trait controlled by many genes, such as human height or skin colour. It is not a type of cross.
• Non-disjunction: failure of chromosomes to separate properly during meiosis, giving gametes with extra or missing chromosomes (e.g. Down syndrome). It is not a type of cross.
• Inbreeding: mating between closely related individuals with similar genetic makeup. It is the opposite of what the question describes.

Step 3: Work through the options

• A. "croos breeding" is a typo for cross breeding. It matches the definition: same species, different genetic characters. ✔
• B. Polygenic inheritance is about gene control of a trait, not a crossing. ✘
• C. Non-disjunction is a meiotic error. ✘
• D. Inbreeding involves genetically similar, related individuals. ✘

Step 4: Answer The correct option is A, cross breeding.

Exam tip: Link the word with its meaning. Cross means different parents, so genetically different. In means within a close family, so genetically similar. Also, whenever you see "-genic inheritance" with "poly", think many genes, not a mating type.