Species-specific sperm attraction has been documented in numerous species. In echinoderms, sperm are attracted toward eggs of their species by chemotaxis. Following statements are about chemoattraction-

A. In this process Sperm follows a gradient of a chemical secreted by the egg.

B. These oocytes control only the type of sperm they attract, but not the time at which they attract them.

C. Releasing the chemotactic factor only when the sea urchin egg has completed all of its meiotic divisions .

D. Releasing the chemotactic factor only when the sea urchin egg is in second metaphase of its meiotic division.

E. The mechanisms of chemotaxis differ among species and chemotactic molecules are different even in closely related species.

Which of the following statement are incorrect about this process?

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#Question id: 12220

#Unit 7. System Physiology – Animal

A female patient has unexplained severe hypernatremia (plasma Na+ = 167 mmol/L) and complains of frequent urination and large urine volumes. A urine specimen reveals that the Na+ concentration is 15mmol/L (very low) and the osmolarity is 155 mOsm/L (very low). Laboratory tests reveal: plasma renin activity = 3 ng angiotensin I/ml/hr (normal = 1.0), plasma antidiuretic hormone (ADH) = 30 pg/ml (normal = 3 pg/ml), and plasma aldosterone = 20 ng/dL (normal = 6 ng/dL). Which of the following is the most likely reason for her hypernatremia?

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#Question id: 12221

#Unit 7. System Physiology – Animal

Juvenile (type I) diabetes mellitus is often diagnosed because of polyuria (high urine flow) and polydipsia (frequent drinking) that occur because of which of the following?

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#Question id: 12222

#Unit 7. System Physiology – Animal

In acidosis, most of the hydrogen ions secreted by the proximal tubule are associated with which of the following processes?

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#Question id: 12223

#Unit 10. Ecological Principles

Evidence shows  that some grasses benefit from being  grazed. Which of the following  terms would  best describe this plant-herbivore interaction?

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#Question id: 12224

#Unit 10. Ecological Principles

Which of the following terms best describes the interaction between termites and the protozoans that feed in their gut?

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#Question id: 12225

#Unit 10. Ecological Principles

Which of the following interactions can correctly be labeled coevolution?