YUCCA
Yucca is a plant in the agave family that has stiff, sword-like leaves and clusters of white or purplish waxy flowers. This succulent plant is pollinated by the yucca moth. The Joshua tree (Y. brevifolia) is a type of yucca. Classification: Division Magnoliophyta, Class Liliopsida (monocots) , Subclass Lilidae, Order Liliales, Family Agavaceae (Agaves), Genus Yucca, many species.

Zinnia
Zinnias are a genus of flowering annual plants that are native to Mexico. Zinnias are named for J. G. Zinn (1727-1759), a German botanist.

ZYGOTE
A zygote is a diploid cell formed by the union of two gametes (it results from the union of an egg cell and a sperm cell).