It is now thought that the atmosphere of the primitive Earth was composed largely of carbon dioxide, nitrogen, and water vapor. The composition of certain iron-containing minerals suggests that the carbon dioxide began to be replaced by oxygen about 2 billion years ago.   Which of the following is the best explanation for the change in atmospheric composition?

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#Question id: 7763

#Unit 5. Developmental Biology

Two major sources of mutation are radiation and reactive oxygen species (ROS).The reactive oxygen species hypothesis for aging postulates that 

1) Senescence results from the accumulation of DNA, lipid, and protein damage inflicted by ROS of mitochondrial origin; and

2) Mitochondria of long-lived species should produce high ROS than do mitochondria of short-lived species.

3) the capacity of mitochondria to consume ROS might distinguish long-lived species from short-lived species, rather than differences in ROS generation. 

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#Question id: 13165

#Unit 5. Developmental Biology

One of the main ways by which the insulin signaling pathway might function to lower longevity is to activate mTORC1, a protein kinase complex that promotes the translation of mRNA into proteins in response to nutrients and hormones, select incorrect statement;

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#Question id: 7286

#Unit 5. Developmental Biology

Which of the floral whorls is affected in apetala 3/pistillata (ap3/pi) mutants?

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#Question id: 7305

#Unit 5. Developmental Biology

In plants, a growing mass of unorganized and undifferentiated cells that cover a wound; these cells can be induced to form a plant meristem and develop into shoots and/or roots called as

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#Question id: 7307

#Unit 5. Developmental Biology

Which of the following statements regarding flowering plants is correct?

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#Question id: 7310

#Unit 5. Developmental Biology

Which statement best describes the mechanism for circadian rhythm?