If a person lived several years without any noticeable signs of viral infection and then one day suddenly fell ill, which of the following provides the best reason as to why? a. Everything in the person’s internal and external environment remained the same b. The individual was surprised all of a sudden by a group of friends c. Something in the individual’s internal environment changed d. The individual watched a horror film*

Climate warming trends allow plant and insect species to inhabit larger ranges. select the best answer from the choices provided

Crinoids, also known as sea lilies, appear to be sea plants but are not plants at all. crinoids are an echinoderm species which uses anchoring structures called holdfasts to attach themselves to the sea floor. crinoids were most abundant in pennsylvania during the mississippian period, which ranged from 375 to 320 million years ago. fossils of the crinoids shows that during most of this time pennsylvania was that provided favorable conditions for crinoid growth. a) glacial terrain b) a dry and sandy plain c) mostly mountain ranges d) covered by warm, shallow seas

Under which of the following circumstances would natural selection not operate on an organism