Prokaryotic cells don't have a nucleus
Chromosomes are thread-like structures in which DNA is tightly packaged within the nucleus.
Answer:
Endocytosis is a form of active transport hence require enegry powered by ATP. The amoeba needs to change shape and engulf and envaginate the particle and then use vessicle transportation to get the materials into the cell. This requires that the cytoskeleton - composed of tubules and filaments - contracts and relax accordingly. This requires energy by ATPs just like the myosin and actin of muscle.
Phagocytosis, another form of endocytosis, is used by some cells such as immune cells to engulf foreign material and then destroy them by use of lysozymes. This is how phagocytes protect the body from invaders.
Answer:
Birds have a different mating season this evidence will go against the argument and suggest that the birds are actually different species. Generally, two factors seasonal and behavioral identifies the differences among the species. Species generally interbred among the same population of species according to the season and hence they loose mating opportunities. Although being sexually compatible they do not interbreed. Behaviorally, a biological clock in species naturally sets breeding cycle according to the resources availability, suitable nesting sites and mating opportunities. Different species have different seasonal requirements to accomplish this.
