These small motile gametes fertilize ovum

Gametes are the reproductive cells of an organisms. They are commonly called also as sex cells. The gametes that fertilize ovum are called sperm, which are the male gametes. Female gametes are known as ova or egg cells. The ova mature in female ovaries whereas the sperm develop in the male testes. 

some fungi obtain their nutrients from a living host (plant or animal) and are called most biotrophic fungi have fairly narrow host ranges—they are specialized on a limited called rhizomorphs that allow the fungus to grow from one tree to another. ascospores are formed inside a sac-like structure called an ascus. so your answer is a

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

explanation: