3 a Why is it useful for crabs that live on the sea shore to have both lungs and gills.

b If equal volumes of blood go through the lungs and gills of light-blue

soldier crabs, suggest the mean percentage of oxygen that would be found in

the blood having gone through only the gills. Explain your reasoning.

c What does this tell you about how efficient both lungs and gills are in these

crabs?

d Suggest three reasons for this difference.

Air pollution is only caused by human activity, select the best answer from the choices provided ot of true or false

Nteractions between organisms and their environment impact the organism’s overall population. oahu amakihi and kauai amakihi are two closely related species of hawaiian honeycreepers. they have a common ancestor, eat small insects and nectar, and like to nest in koa trees. however, one species is found on the island of oahu, and the other is found on the island of kauai. which concept shows the relationship between oahu amakihi and kauai amakihi?

The table below shows the number of foot bones in some horse fossils. horse fossil recordhorse fossil number of foot bonesp 19q 17r 24s 13ancient horses had more bones in their foot then present-day horses. the present-day horse has 11 foot bones. what is the correct order of evolution of the horse starting from the youngest fossil? a. q p r s b. s r p q c. s q p r d. r p q s