#Question id: 5051
#Unit 5. Developmental Biology
fter the 8-cell stage, the mammalian embryo develops an outer layer (which becomes the fetal portion of the placenta), and an inner cell mass that generates all the cells of embryo. The cells of the inner cell mass are thus said to be-
#Question id: 19376
#Unit 12. Applied Biology
#Question id: 9617
#Unit 9. Diversity of Life Forms
The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed 3-chambered hearts (2 atria, 1 ventricle). Birds and mammals, however, are alike in having 4-chambered hearts (2 atria, 2 ventricles). The 4-chambered hearts of birds and mammals are best described as
#Question id: 19994
#Unit 2. Cellular Organization
#Question id: 11422
#Unit 10. Ecological Principles
The values of temperature and precipitation used to define climate zones correspond to the conditions of moisture and cold stress that are particularly important determinants of plant form. Which of following is correct combination of Biome?
