QUES: If Mammalia is considered as the crown group, its origin can be roughly dated as the first known appearance of animals more closely related to some extant mammals than to others. Ambondro is more closely related to monotremes than to therian mammals while Amphilestes and Amphitherium are more closely related to the therians; as fossils of all three genera are dated about 167 million years ago in the Middle Jurassic, this is a reasonable estimate for the appearance of the crown group. The earliest known synapsid satisfying Kemp's definitions is Tikitherium, dated 225 Ma, so the appearance of mammals in this broader sense can be given this Late Triassic date. In any case, the temporal range of the group extends to the present day.
About what year are ambondro dated to?

ANS: unanswerable

QUES: In abstract algebra, more general structures are defined by relaxing some of the axioms defining a group. For example, if the requirement that every element has an inverse is eliminated, the resulting algebraic structure is called a monoid. The natural numbers N (including 0) under addition form a monoid, as do the nonzero integers under multiplication (Z {0}, ), see above. There is a general method to formally add inverses to elements to any (abelian) monoid, much the same way as (Q {0}, ) is derived from (Z {0}, ), known as the Grothendieck group. Groupoids are similar to groups except that the composition a b need not be defined for all a and b. They arise in the study of more complicated forms of symmetry, often in topological and analytical structures, such as the fundamental groupoid or stacks. Finally, it is possible to generalize any of these concepts by replacing the binary operation with an arbitrary n-ary one (i.e. an operation taking n arguments). With the proper generalization of the group axioms this gives rise to an n-ary group. The table gives a list of several structures generalizing groups.
What type of numbers under addition form a monoid?

ANS: natural numbers N (including 0)

QUES: At a minimum, HDTV has twice the linear resolution of standard-definition television (SDTV), thus showing greater detail than either analog television or regular DVD. The technical standards for broadcasting HDTV also handle the 16:9 aspect ratio images without using letterboxing or anamorphic stretching, thus increasing the effective image resolution.
HDTV increases the effective image resolution by not using what?

ANS: letterboxing or anamorphic stretching

QUES: Tibetan music often involves chanting in Tibetan or Sanskrit, as an integral part of the religion. These chants are complex, often recitations of sacred texts or in celebration of various festivals. Yang chanting, performed without metrical timing, is accompanied by resonant drums and low, sustained syllables. Other styles include those unique to the various schools of Tibetan Buddhism, such as the classical music of the popular Gelugpa school, and the romantic music of the Nyingmapa, Sakyapa and Kagyupa schools.
What type of music comes from the popular Gelugpa school?

ANS:
classical