Answer:
Earliest- gametophyte dominance, sporophyte dependence
Middle- sporophyte dominance, gametophyte independence
Recent- sporophyte dominance, gametophyte dependence
Explanation:
The life cycle of plant alternates between the two phases: the haploid gametophyte which produces gametes and the diploid sporophyte which produces spores. The evolution of land plants shows how these are dependent on each other in terms of the requirement of nutrition.
In bryophytes, the gametophyte is the dominant phase on which the sporophyte depended. Later in pteridophytes, the sporophyte became dominant which is present in the later evolved groups namely the gymnosperms and the angiosperms. The gametophyte was independent on the sporophyte but in angiosperms and gymnosperms, it is dependent.
The correct answer is option D, Temporal isolation
Temporal isolation is the mechanism which prevents the mating of closely related species living in the same ecosystem. Basically the reproductive barriers prevent these species from interbreeding. Temporal isolation is a prezygotic barrier that causes “time isolation” between the breeding period of two closely related species. The difference in time could be “difference in time of day”, “ difference in season of mating”, “difference in months” and in some cases “ difference in years”.
1. A
2. A
3. C
I hope this helps:)
Answer:
b. thick wall.
Explanation:
Endospore is a structure formed by some bacteria, that help them survive unfavourable conditions (e.g. lack of nutrients). This survival strategy of some bacteria (usually Gram+ bacteria) help them stay dormant for a while, until stressful conditions stop. A thick wall composed of many layers (exosporium, spore coat, spore cortex, core wall) of the endospore is what provides resistance to different stressful chemical and physical factors such as UV radiation, temperature, chemical damage etc.
Answer:
The answer is D good luck
