Before nitrogen gas can be used by living organisms it must be converted into ammonium. This important step of the nitrogen cycle is known as 1. ammonification
2. denitrification
3. ozonation
4. nitrification​

Match the reproductive structures based on their function and the system to which they belong. egg ovary sperm vas deferens vagina fallopian tube testis urethra

Temperatures in ponds and lakes vary by season. select the best answer from the choices provided t f

Rarefaction is used for which of the following? a. creating a representative sample b. studying how disease impacts populations c. rediscovering species thought to be instinct d. determining which sea creatures live in an area