Tropical forests contain dense trees, which allow less sunlight to penetrate. emergent trees are trees that grow to a height of more than 45 to 55 meters, above the usual height of trees in tropical forests. which system provides the best possible explanation for why these trees grow to those heights?
a: growth pattern
b: homeostasis
c: nervous system coordination in plants
d: phototropism

What protects the lining of the stomach from acidic gastric juices?

The observations of hooke and van leeuwenhoek documenting the existence of microscopic cells formed the basis of what important theory? a. the cell theory stating that all living things are composed of cellsb. the theory of spontaneous generation, which held that life forms could arise spontaneouslyc. the theory of chemotherapy, or use of antimicrobials to destroy pathogenic organismsd. the germ theory of disease and causative agents

Which codon is the code for the amino acid histidine (his)?