Damage to cells in the embryo's layer would be most likely to result in the development of a defective digestive system. Select one: a. placenta b. endoderm c. ectoderm d. mesoderm

Which of the following is not a main characteristic that scientists focus on when determining which kingdom an organism belongs to

Which of these statements best describes the st. lawrence seaway? the st. lawrence seaway connects the st. lawrence river with the arctic ocean. the st. lawrence seaway provides an important trading route between the u.s. and mexico. the st. lawrence seaway provides an important trading route for the u.s, but has little value for canada. the st. lawrence seaway connects the great lakes, the st. lawrence river, and the atlantic ocean.

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?