Some pituitary hormones cause the ovaries to secrete hormones. these ovarian hormones then influence the production of the pituitary hormones. this type of control mechanism is known as
1) a menstrual cycle
2) ovulation
3) gametogenesis
4) negative feedback

The construction of phylogenetic trees is a mapping out the proposed divisions and common ancestors of all living species. traditionally, these trees have been built using morphological data, such as appearance and embryology. recently, it has been possible to construct these trees using molecular data. phylogenetic trees based on different types of information agree with each: that there is strong evidence of a real underlying common descent. this phylogenic tree is composed based on molecular data (rrna). what statements can we infer are true about the organisms throughout the tree? because the tree is rooted, all branches share a common ancestor. all organisms have some sort of cellular structure/organization. all eukaryotes evolved from bacteria. since the organisms contain rna, they share the same dna. if the organisms contain rna, the share the same four nitrogen bases.

Ageologist determines that a sample of a mineral cant be scratched by a steel nail but can be scratched by a masonry drill bit based on this information the sample mineral has to be softer than

During the winter, this species of fox has white fur, but in the summer, it has brown fur. what environmental change may have lead to this fox's fur color? snow cover increase in sun's brightness volcanic eruption global warming