1. In ecological studies, sampling methods are used in three ways: random sampling (large numbers of samples are taken from different points of the habitat), systematic sampling (samples are taken at fixed intervals along a line), and stratified sampling (samples are taken from different areas located within the main region of a habitat). These methods allow counting of the individuals and species during a specific period.
2. The main ethical issues related to human cloning and using embryonic stem cells comprise: the destruction of the human embryo, absance of the laws providing the control of the procedure, assuring that women donating eggs give proper informed consent (autonomy), non-commercialization, safety and utility, and increased rate of illegal abortion.