NIDDK, NIH
Along with having smooth edges and lacking organelles, red blood cells are also specialized to have a concave shape. How does the
shape of a red blood cell help it to perform its specific function in the human body?
A.
This shape increases the surface area of the cell, which allows it to bind and transport oxygen more easily.
B.
This shape decreases the volume of the cell, which allows the cell to cross semipermeable membranes more easily.
c.
This shape increases the volume of the cell, which allows it to store more carbon dioxide for transport.

This shane decreases the surface area of the cell, which makes the cell less susceptible to infection.

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.

African penguins, which inhabit the coasts of southern africa, were classified as an endangered species in 2010. two significant threats to their survival are ecosystem damage from oil spills and overfishing by humans. overfishing depletes the food supply of african penguins. the best method to reduce the threat of overfishing would be to . the risk of oil spills could be reduced by increasing the use of , which should oil consumption. if an oil spill does occur, could be used to remove the oil so the ecosystem may more quickly recover.

What are some natural processes that represent physical and chemical changes?