What directs similar cells to change into a specific organ?

Asap timed! 1. ice core samples from glaciers ice caps contain bubbles of ancient atmosphere that are in layers based on age. what questions are scientists most interested in? a. how the amount of water vapor needed to make the ice has changed b. how the amount of ozone has changed over time. c. how the amount of ice in each layer has changed over time d. how the amount of carbon dioxide has changed over time 2. what produces milankovich cycles ? a. sunspots ams solar flare on the suns surface b. changes in the earths orbit c. gravitational changes bases on the position of the sun and the moond. cycles of vegetation that result in desert and rainforest conditions

Describe five factors that influence the value of fuel

The transport tubes for food coming down the plants are called?