Why are some leaves spiny, or needle-shaped?

Explain how the number of similarities between the embryos from early stage to late stage is used as evidence of a common ancestry

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.

What do we call the process when two dominant alleles are expressed and do not blend? a.incomplete dominance b.codominance c.multiple alleles