*Question*
Answer the following question given this paragraph: Air movement takes place in the troposphere. This is the lowest layer of the atmosphere. Air moves because of differences in heating. These differences create convection currents and winds ( Figure below ). Q: What is the lowest layer of the atmosphere called? Choices: - mesosphere - lithosphere - asthenosphere - troposphere A:
**Answer**
troposphere

*Question*
Answer the following question given this paragraph: The phylum Annelida is made up of segmented worms such as earthworms. Segmented worms are divided into many repeating segments. There are roughly 15,000 species of annelids. Most belong to one of three classes. A species in each class is pictured in Figure below . Q: Which phylum is made up of segmented worms such as earthworms? Choices: - chordata - arthropod - nematoda - annelida A:
**Answer**
annelida

*Question*
Answer the following question given this paragraph: The placenta is a spongy structure. It consists of membranes and blood vessels from both mother and embryo (see Figure below ). The placenta passes oxygen, nutrients, and other useful substances from the mother to the fetus. It also passes carbon dioxide and other wastes from the fetus to the mother. The placenta lets blood from the fetus and mother exchange substances without actually mixing. Thus, it protects the fetus from being attacked by the mother's immune system as a "foreign parasite. ". Q: Designed to exchange materials, what spongy structure consists of membranes and blood vessels from both mother and embryo? Choices: - endometrium - uterus - umbilicus - placenta A:
**Answer**
placenta

*Question*
Answer the following question given this paragraph: For feeding, the insect head contains one pair of lower jaws and two pairs of upper jaws. Insects have also evolved a wide range of specialized mouthparts for eating certain foods. You can see some examples in Figure below . Q: How many pairs of upper jaws do insects have? Choices: - four pairs - six pairs - three pairs - two pairs A:
**Answer**
two pairs