A large proportion of archaeans are extremophiles, so called because they inhabit extreme environments with high acidity, salinity, and/or temperature. Such environments are thought to have been much more common on primitive Earth. Thus, modern extremophiles survive only in places that their ancestors became adapted to long ago. Which of the following is, consequently, a valid statement about modern extremophiles, assuming that their habitats have remained relatively unchanged?

#Question id: 10506

#Unit 6. System Physiology – Plant

Plant growth promoting rhizobacteria (PGPRs) such as Pseudomonas aeruginosa, that alleviate plant abiotic or biotic stress in soil by releasing of

#Question id: 10507

#Unit 6. System Physiology – Plant

Rhizobacteria function as

 a) Nitrogen fixation

 b) depositing pathogens directly into the vascular system,

 c) producing antibiotics and antifungal agents for inhibiting soil pathogens

 d) herbivore sensors by sending electrical or chemical signals to surrounding cells

 Which one of the following combination is correct?

#Question id: 10508

#Unit 6. System Physiology – Plant

Glandular trichomes store species-specific secondary metabolites in a pocket formed between the cell wall and the cuticle. These secondary metabolites are-

#Question id: 10509

#Unit 6. System Physiology – Plant

A different type of mechanical obstacle to herbivory is provided by mineral crystals that are present in many plant species, such as silica crystals known as

#Question id: 10510

#Unit 6. System Physiology – Plant

Constitutive chemical defenses are effective against many different herbivores, including insects and mammals. Hemlock (Cicuta sp.) produces which toxins that a polyacetylene prolongs the repolarization of neuronal action potentials.

#Question id: 10511

#Unit 6. System Physiology – Plant

Which type of pumps inhibits digitoxin in the membranes of heart cells, leading to increased myocardial contraction?