All fertilization requiresa) an internal environment.b) an external environment.c) critical timing.d) a developed reproductive system

The correct answer is c) critical timing. Fertilization requires precise timing for the sperm to meet the egg. This is because an egg is usually only viable for a short period after it has been released (ovulation). If the sperm does not meet the egg within this time, fertilization will not occur. This is true for both internal and external fertilization. While a developed reproductive system is necessary for fertilization, it is not the fertilization itself that requires it. Therefore, the most accurate answer is c) critical timing.