If the scientific name of the tiger is Panthera tigris then: to what genus do tigers belong?

Panthera.

hope this helps!

Well, all of them are as important as each other. Without the roots the plant would not be able to get the nutrients  and water from the soil. Without the leaves the plant wouldn't be able to transpire, to release water vapor from its pores. On the other hand, flowers have the sex organs for the plants, the male and female parts so the plant can "reproduce". And sorry since I skipped stem. The stem is the part that hold the plant, in side the stem there is the xylem which is a tube that transports water and minerals through the plant, also inside the stem there in the Phloem which is a tube in the plant that transport the food and hormones of the plant. Hope this helped, sorry that it's too long!