Antibodies, also known as immunoglobulins, play a crucial role in the immune system by identifying and neutralizing foreign invaders such as bacteria, viruses, and toxins. Produced by B cells, antibodies are proteins that specifically bind to antigens, which are unique molecules found on the surface of pathogens.

Once an antibody binds to an antigen, it can neutralize the pathogen directly by blocking its ability to infect cells. Additionally, antibodies can mark pathogens for destruction by other immune cells, a process known as opsonization. This enhances the efficiency of phagocytes, like macrophages, which engulf and digest the marked invaders.

Antibodies also activate the complement system, a group of proteins that assist in destroying pathogens. There are different classes of antibodies (IgG, IgA, IgM, IgE, and IgD), each with specific functions and locations in the body, contributing to a well-coordinated immune response.

Overall, antibodies are essential for adaptive immunity, providing long-lasting protection and memory against previously encountered pathogens, which is the basis for vaccination.

Migratory animals are species that travel from one region to another, often seasonally, in search of better living conditions. This behavior is primarily driven by the need for food, breeding, and suitable habitats. Common examples include birds, such as the Arctic Tern, which migrates thousands of miles between breeding and wintering grounds, and mammals like caribou, which move to find food and avoid harsh weather.

Migration allows animals to exploit seasonal resources. For instance, many birds migrate to warmer climates during winter to access abundant food sources and favorable breeding conditions. Similarly, marine species like salmon migrate upstream to spawn in freshwater rivers, ensuring the survival of their young.

Additionally, migration can help animals avoid predators and harsh environmental conditions. By moving to different areas, they can find safer habitats and reduce competition for resources. Overall, migration is a crucial survival strategy that enables animals to adapt to changing environments and maintain their populations.