Echinoderms are defined as any of a variety of invertebrate marine animals characterized by a hard, spiny covering or skin. They have attracted much attention due to their extensive fossil record, ecological importance, and bizarre body forms. Most echinoderms are extinct, but many living representatives still exist. All living echinoderms have an internal skeleton and a central cavity, but the outward appearance can vary significantly. For example, starfish and brittle stars have arms that extend from a central disk; sea lilies have a central stalk, or stem, and resemble flowers; sea cucumbers are wormlike and tend to burrow. The ways in which echinoderms move and feed are as diverse as their body forms. Table 1 lists certain echinoderms and their methods of locomotion (movement) and feeding Table 2 includes examples of echinoderms habitats around the world. According to Table 1 and Table 2, crinoids can be found feeding on plankton:

Echinoderms are defined as any of a variety of invertebrate marine animals characterized by a hard, spiny covering or skin. They have attracted much attention due to their extensive fossil record, ecological importance, and bizarre body forms. Most echinoderms are extinct, but many living representatives still exist. All living echinoderms have an internal skeleton and a central cavity, but the outward appearance can vary significantly. For example, starfish and brittle stars have arms that extend from a central disk; sea lilies have a central stalk, or stem, and resemble flowers; sea cucumbers are wormlike and tend to burrow. The ways in which echinoderms move and feed are as diverse as their body forms. Table 1 lists certain echinoderms and their methods of locomotion (movement) and feeding Table 2 includes examples of echinoderms habitats around the world. The echinoderm shown below is most likely a:

Predation is an interaction between individuals of 2 species in which one is harmed (the prey), and the other is helped (the predator). Predation can occur among plants and animals as well as between plants and animals. Some biologists contend that herbivores, or plant eaters, are predators. Table 1 indicates some characteristics and examples of certain predators. According to information in the passage, the number of prey consumed in an ecosystem is dependent on:

Passage I The figure below is a pedigree that shows the inheritance of a trait, Trait G, in a family. The presence of Trait G in an individual is determined entirely by Gene G. Gene G has 2 alleles: G, which is dominant, and g, which is recessive. Each individual represented in the pedigree was assigned a number (shown below the symbol for the individual) for reference. Scientists determined that the Gene G genotype of Individual 20 is gg and that the Gene G genotype of Individual 21 is Gg. Based on this information, the scientists concluded that Trait G is a recessive trait. Suppose that Individual 23 and Individual 24 have 4 biological children. Based on the figure, how many of the children, if any, have Trait G?

Echinoderms are defined as any of a variety of invertebrate marine animals characterized by a hard, spiny covering or skin. They have attracted much attention due to their extensive fossil record, ecological importance, and bizarre body forms. Most echinoderms are extinct, but many living representatives still exist. All living echinoderms have an internal skeleton and a central cavity, but the outward appearance can vary significantly. For example, starfish and brittle stars have arms that extend from a central disk; sea lilies have a central stalk, or stem, and resemble flowers; sea cucumbers are wormlike and tend to burrow. The ways in which echinoderms move and feed are as diverse as their body forms. Table 1 lists certain echinoderms and their methods of locomotion (movement) and feeding Table 2 includes examples of echinoderms habitats around the world. Based on the data provided in the passage, sea cucumbers most likely burrow in order to:

A student hypothesised that large populations of sea cucumbers could greatly alter the physical and chemical composition of the sea floor. Is this hypothesis supported by the data in the passage?

A mercury thermometer, at an initial temperature of 20◦C, was placed in 40◦C water, and the temperature registered by the thermometer was recorded over time. This procedure was repeated using water samples at 50◦C and 60◦C (see Figure 1). Next, the same thermometer, at an initial temperature of 60◦C, was placed in an air sample at 50◦C, and the temperature registered by the thermometer was recorded over time. This procedure was repeated using air samples at 30◦C and 40◦C (see Figure 2) Based on Figure 1, at 3.0 sec, the thermometer reading in the 40°C water most likely was closest to which of the following?