Explain why 2 brothers may look very different if they have the same parents. Be sure to write in complete sentences and use the term "crossing over".

Wildlife can be scarce in many large, densely populated cities. A few plants and animals can be found in these areas. For example, rats, mice, pigeons, cockroaches, and other insects are common in cities.

Based on linnaeus's classification system, which pair of organisms have a common relationship?

Can we accelerate or slow down the natural evolution process of mankind? Why or Why not?

What might happen to populations that cannot get enough resources?

Almost 50 percent of water withdrawn in the US, is used up by thermoelectric power plants. The table below shows the amount of water withdrawn in the U. S., in billion gallons per year, between 1950 and 2005.

Which statement best describes the relationship between activation energy and rate of reaction? O Increasing the activation energy can increase the rate of a reaction. O Reducing the activation energy can increase the rate of a reaction.

Definition: this is a haploid cell with half the reproductive information from the parent.

Does a cell use energy when molecules diffuse in or out of the cell? Why?

Below is a list of possible challenges. Check all errors that you mentioned in your answer. Traits other than beak type might affect natural selection. It could take many generations to observe adaptions to a population.

A farmer dug a well but did not find any water Which reasons most likely explain why the farmer did not find water? Check all that apply.