In order for cells in multicellular organisms to exchange gases, a circulatory system must be present.
a. true
b. false

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks

Select the correct answer. for their summer holiday, jane and her family are visiting places surrounding the mediterranean sea. which type of biome is jane and her family visiting? a. rainforest b. shrubland c. tundra d. coniferous forest reset next

An adult inhales about 6.0×10−4 m3 of fresh air during a breath. only 20% of fresh air is oxygen. assume the pressure in the lungs is 1.0×105 paand the air is at a temperature of 300 k. how many oxygen molecules are in each breath? a. 1.4x10^23 b. 2.9x10^21 c. 4.9x10^-4 d. 2.9 x10^25