Food chains are typically quite short, with only 4-5 links.Which of the following explains why? Only one species of herbivorefeeds on each producer species. Predator species are usually lessdiverse and less abundant than prey species. Most of the energy ateach trophic level is lost rather than passing on to the nextlevel. Extinction of species at one level causes extinctions athigher levels. 1 points

QUESTION 47 Which of the following is a characteristic of allchordates at some point during their life cycle? vertebrae fourlimbs four-chambered heart jaws post-anal tail 1 points

QUESTION 48 Which of these is a major trend in land plantevolution? the trend toward larger gametophytes the trend towardsmaller size the trend toward a gametophyte-dominated life cyclethe trend toward a sporophyte-dominated life cycle 1 points

QUESTION 49 The phytochrome system is involved in which of thefollowing plant responses? none of the responses involve thephytochrome system photoperiodism all of these responses involvethe phytochrome system negative phototropism positive phtotropism 1points

QUESTION 50 Approximately how many kilocalories (kcal) of asecondary consumer's energy requirements can be supported by acommunity containing 100 kcal of producers? 0.1 kcal 10 kcal 1 kcal0.01 kcal 1 points

QUESTION 51 Vertebrates and urochordates share which of thefollowing traits? a high degree of cephalization (i.e., awell-developed head) a notochord and a dorsal, hollow nerve cordvertebral column jaws adapted for feeding