Proper division of chromosomes fails more frequently in mammalian oogenesis than in mammalian spermatogenesis. What is the most likely reason for this phenomenon? a. Crossover events occur in oogenesis but do not occur in spermatogenesis.
b. Oogenesis creates polar bodies, whereas spermatogenesis does not.
c. Primary oocytes are haploid, whereas primary spermatocytes are diploid.
d. Oogenesis is arrested in prophase I, whereas spermatogenesis is not arrested.

4.06 hc)a five-year review of threats to the southern resident orca population of the united states concluded that the top threats were prey availability, contaminants, and effects from recreational and whale watching vessels. further down the list are oil spills, disease, and effects from commercial vessels not targeting whales. how might this list be different if it were for transient whale populations, which have a larger average population size and live farther offshore in open waters? a)the transient population is more likely to be affected by contaminants. b)the transient population is less likely to be affected by whale watching vessels. c)the transient population is more likely to be affected by disease. d)the transient population is less likely to be affected by prey availability.

The organelle pictured is found in cells of and is theorized to have once been an independent organism.

Directions: read the descriptions of the four islands presented in the lesson. 1. list two new traits that each new species of rat might demonstrate as it adapts to the conditions on each island. 2. introduce one of the four new rat species to another island and describe one challenge it would encounter and one success as it adapts to its new environment.