Why are scientists concerned about the use of the Bt toxin, which is used to kill insects, in genetic engineering?
The Bt toxin is killing too many insects.
The Bt toxin stays in the soil for long periods of time.
The Bt toxin gene is not readily accepted by plants.
The Bt toxin has been known to cause disease in plants.

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.

Which statement describes characteristics of planarians? a they live in oceans, are parasites, and reproduce only sexually. b they live in fresh water, are parasites, and reproduce only asexually. c they live in oceans, are free living, and reproduce sexually and asexually. d they live in fresh water, are free living, and reproduce sexually and asexually.

The climate on the leeward side of a mountain differs from that on the windward side mostly in