Hemoglobin, an oxygen-carrying protein found in the red blood cells of vertebrates, helps to circulate oxygen from the lungs to all parts of the body. In penguins, the blood has a very high concentration of hemoglobin. Penguin muscles have a high concentration of myoglobin, which also stores oxygen. What might be a reason for these adaptations? What are the sequence of conditions and events that had to occur for the trait to become an adaptation.

Complete the sentences by matching the names of trees to the appropriate blanks. to do this, drag the names on the left into the appropriate blanks in the sentences on the right. match the words in the left column to the appropriate blanks in the sentences on the right. terms may be used more than once. make certain you have filled every blank with a term before clicking submit. 1. deciduous trees lose their leaves seasonally and include trees such as maple and elm. 2. conifer leaves are generally thin and needle-like, while seeds are contained in cones. conifers include cedar and pine. 3. evergreens are plants that maintain their leaves in all seasons and include trees such as cedar, elm, and pine. 4. hardwoods reproduce using flowers and have broad leaves; hardwoods include trees such as maple, , and cedar. elm returned you filled in 2 of 10 blanks incorrectly. mango trees are tropical broad leaf plants that maintain their leaves all year long. no credit lost. try again.

What does the hardy-weinberg principle relate to? a. chances of survival of an organism b. frequency of alleles in a population c. natural selection in a species d. causes of evolution among organisms

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere