For maximum photosynthesis, increased light intensity has greater effect than increased leaf surface area.
a. true
b. false

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

Imagine a self-reactive t cell that has not undergone clonal deletion in the thymus (that is to say, it has escaped central tolerance). if it encounters self antigen in the absence of an infection or inflammation, what will happen to this self-reactive t cell? (select two answers) (a) the t cell undergoes clonal expansion. (b) the t cell gains effector functions. (c) the t cell undergoes apoptosis. (d) the t cell becomes activated. (e) the t cell becomes anergic.

Earth is tilted on its axis. which of these would not exist if earth had no tilt?