What term is used for the situation where leaves are growing pointing downward because the cells on the upper side of the leaf petiole (stem) are growing faster than the cells on the lower side of the petiole?

Phytochrome is both a pigment and, in its active form, what kind of enzyme?

It is considered to be the warmest ocean:

Diatoms always reproduce asexually, regardless of their size.

The study of the distribution of organisms in geographic space is called: 

Represents the movement of organisms from one location where they feed, vs the location where they reproduce: 

Auxin can be transported through the plant either by polar transport or by the vascular tissue system.  Which of the following statements is true about these methods of auxin transport?

These hormones are synthesized from amino acids.

Although optimal levels of auxin promote growth and inhibit leaf abscission, when auxin concentration get too high, the opposite things happen (growth is inhibited and abscission is promoted).  Which of the following explain the reason for these opposite effects?

The list below includes several strategies that certain tree species have to survive freezing temperatures. Choose the SECOND of the two options in the list that indicates a strategy that some tree species have to survive freezing temperatures