A stem-cell niche is an area of a tissue that provides a specific micro-environment, in which stem cells are present in an undifferentiated and self-renewable state.
Meiosis produces 4 haploid cells.
<span>The sympathetic division of the autonomic nervous system is active just before the race because it functions to mobilize resources of the body for energy expenditure and as well metabolism, for the purposes of increasing physical activities inside the body such as blood pressure, heart rate, breathing rate, which are important aspects during exercises</span>
1. C
2. D (remember that A always pairs with T and G always pairs with C)
3. B
4. I do not know number four but I hope this helps!!!
The answer is A! Speciation is the right answer
