Answer:
Nitrogen is converted from atmospheric nitrogen (N2) into usable forms, such as NO2-, in a process known as fixation. ... This occurs in two steps: first, bacteria convert ammonia in to (nitrites) NO2-, and then other bacteria species convert it to NO3- (nitrate). Nitriates are a form of nitrogen that is usable by plants.
Explanation:
C
The medow has been hit by a fire, which means, there is not much medow left. The medow that is left, is being eaten by grasshoppers and since we know that grasshopper populations are big, not all of them will be ablo to feed on the same spot, making the carring capacity of the medow (in terms of grasshoppers) lower.
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BioTeacher101
The given question is incomplete. The complete question is:
All of the flower mechanisms would help prevent pollination by a foreign species except __________.
A. A pollen tube grows in the style of its own species.
B. The stigma is sticky mainly to its own species of pollen.
C. The timing of flowering keeps pollinators moving among a limited number of species.
D. Flowers attract a small number of specialized pollinators, and therefore pollen is not spread equally to all available species of flowers.
E. Flowers of different species are the same color and attract similar pollinators.
Answer:
E. Flowers of different species are the same color and attract similar pollinators.
Explanation:
Plants of different species develop various morphological, physiological and behavioral strategies to ensure that the flowers of one species are not pollinated by pollens from any other species. One such structural adaptation is the production of flowers of a different color, size and shape.
These structural distinctions allow specific pollinators to visit the flowers of the particular species only. It ensures pollens from a different plant species do not land on the flowers of some other species. Production of flowers of the same color by different plant species would attract same pollinators and may result in pollination by a foreign species.
Answer: muscle contraction of sustained force resulting from repeated action potentials. (Option A)
Explanation: Tetanus is also called physiologic tetanus. Tetanus refers to the contraction of the muscle, which is established when the motor nerve that supply nerves to a skeletal muscle produces action potentials at a very high degree.
However, tetanic contraction is usually a normal process (such as when carrying a heavy box). Also, muscles can be shorten, lengthen or remain constant length during tetanic contractions.
seed coat protects the cotyledons and embryo from outer environment and from attack of pathogens
pollen grain has a sculptors covering with weak points(germ pores) in it through which pollen tube comes out.
A spore is generally protected by 2-3 tough resistant walls around to tied over the unfavourable conditions.