What were the oldest living things from 3.5 billion years ago like?

What happens when the cell copies its chromosomes

The unique structure of the neuron is dedicated to the efficient and rapid transmission of neural signals. the relationship between neurons, the spinal cord, and the brain constitutes an elaborate communication system throughout the human body. all but one of the functions listed below are a result of this interaction.

Common symptoms of an iron-defiency anemia include muscle weakness shortness of breath and lightheadedness why does iron deficiency causes these symptoms