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TLS Online TPP Program

#Question id: 3275

When imbalances occur in the sex ratio of sexual species that have two sexes (that is, other than a 50:50 ratio), the members of the minority sex often receive a greater proportion of care and resources from parents than do the offspring of the majority sex. This is most clearly an example of ________.

#Unit 11. Evolution and Behavior

sexual selection
balancing selection
stabilizing selection
frequency-dependent selection

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TLS Online TPP Program

#Question id: 5145

#Unit 5. Developmental Biology

Doris Taylor’s research group used detergents to remove all the cells from a cadaveric rat heart, which left behind the natural extracellular matrix. Proteins such as fibronectin, collagen, and laminin held together the rest of the extracellular matrix and maintained the intricate shape of the heart. The researchers then infused this extracellular matrix scaffold with cardiomyocyte progenitor cells. Surprisingly, these cells differentiated and organized into a functionally contracting “recellularized” heart. The behavior of extracellular matrix scaffold can promote the differentiation and rebuilding of a beating heart is analogous to which of the interactions?

TLS Online TPP Program

#Question id: 5146

#Unit 5. Developmental Biology

Choose the correct match.

Process	Definition
a. Epithelial-mesenchymal transition	i. The phenomenon, whereby cells intercalate to narrow the tissue and at the same time lengthen it.
b. De-adhesion	ii. The process in which cells that had formerly been part of an epithelium lose their attachments and become individual, migrating cells.
c. Permissive interaction	iii. The cadherins that couple epithelial cells together are degraded, thereby allowing the cells to become free from their neighbors.
d. convergent extension	iv. The responding tissue has already been specified and needs only an environment that allows the expression of these traits.