Help me please please

Inspired by the example of that great cornellian, vladimir nabokov, some of your friends have become amateur lepidopterists (they study butterflies). often when they return from a trip with specimens of butterflies, it is very difficult for them to tell how many distinct species they've caught— to the fact that many species look very similar to one another. solution

The type of cloud shown here may produce heavy rainfall. this type of cloud most likely occurs in an area of the sub-saharan that is a) often dry. b) often wet. eliminate c) very windy. d) usually cool.

This term refers to the number of people per unit area (usually a kilometer or a mile). this could refer to the number of people per square mile in a city, a county, a province, a state, or a nation.