Respuesta :
Answer:
Explanation:
Most protist diseases in humans are caused by protozoa. Protozoa make humans sick when they become human parasites. Trypanosoma protozoa cause Chagas disease and sleeping sickness. Giardia protozoa cause giardiasis, and Plasmodium protozoa cause malaria.
The process of fertilization is tightly controlled to ensure that only one sperm fuses with one egg. After fertilization, the zygote undergoes cleavage to form the blastula. The blastula, which in some species is a hollow ball of cells, undergoes a process called gastrulation, in which the three germ layers form.
