Biology

2. Type of blood cell that defends the body against infections and foreign invaders.
6. A substance that stimulates the immune system to produce an immune response without causing the disease.
10. Single-celled microorganisms, some of which can cause infections or diseases.
11. A change in the DNA sequence that can lead to variations in traits
12. An immune response to harmless substances, such as pollen or certain foods.
14. Having two different alleles for a particular gene.
18. The process by which a disease-causing agent is passed from one individual to another.
19. The process by which organisms with traits better suited to their environment tend to survive and reproduce more successfully.
20. A microorganism or agent that causes disease or infection in a host.

1. Immune cell that "remembers" a specific pathogen, providing quicker responses during future infections.
3. An allele that expresses its trait even when only one copy is present.
4. Differences in traits among individuals of a species
5. Having two identical alleles for a particular gene.
7. Protein produced by the immune system to neutralize or destroy foreign substances like bacteria or viruses.
8. The passing of genetic traits from parents to offspring.
9. a distinguishing characteristic or feature of an organism.
13. An allele that only expresses its trait when two copies are present, one from each parent.
15. A microscopic infectious agent that requires a host cell to replicate and can cause disease.
16. A characteristic or behavior that helps an organism survive and reproduce in its environment.
17. A substance that triggers an immune response, often found on the surface of pathogens.