It hasn’t rained in several days and you have forgotten to water your fern. The roots sense a lack of water and produce the hormone abscisic acid. Abscisic acid triggers the guard cells to shrink. When the guard cells shrink, the stomatal pore closes and water loss decreases which inhibits the reproductive ability of the flower.

Which of the following choices is not an effective solution to the energy waste related to inefficient lighting? a. using low-pressure sodium lighting sources b. pointing lights on billboards and street signs upward c. placing light sources on time controls d. shielding light to direct it downward

Which sentence is an example of a strong conclusion to an autobiography? a. i stayed after school three days in a row to practice onstage in the auditorium. b. i knew i would have to practice all week to memorize my dance for the recital. c. after the recital was over, i knew practicing was worth it, and i was looking forward to my next big challenge. d. on opening night, i danced in front of a packed auditorium.

How does the study of genetic disorders such as pku biologists understand normal alleles?