As in all animals, the adaptations for reproduction in humans are complex. They involve specialized…

The process by which an organism develops from a single-celled zygote to a multi-cellular organism…

The fusion of a sperm and an egg is a process called fertilization. This can…

Sexual reproduction is the combination of reproductive cells from two individuals to form genetically unique…

Figure 13.1 Female seahorses produce eggs that are then fertilized by the male. Unlike with…

A functioning immune system is essential for survival, but even the sophisticated cellular and molecular…

The innate and adaptive immune responses compose the systemic immune system (affecting the whole body),…

Lymph is the watery fluid that bathes tissues and organs and contains protective white blood…

The adaptive immune system has a memory component that allows for a rapid and large…

Unlike B cells, T lymphocytes are unable to recognize pathogens without assistance. Instead, dendritic cells…