#Question id: 13047
#SCPH06 I Botany
#Question id: 10249
#SCPH06 I Botany
A niche is
#Question id: 6960
#SCPH06 I Botany
At the blastocyst stage during mammalian embryonic development, the specification of trophectoderm requires ________; whereas in inner cell mass _________activation is essential.
#Question id: 15707
#SCPH28 | Zoology
#Question id: 8294
#SCPH05 I Biotechnology
The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The fourchambered hearts of birds and mammals are best described as ________.