The scientist who discovered the bacterium Helicobacter pylori and its role in ulcers was: MCQ with Answer and Explanation

Explanation:
Analogous organs are structures that perform similar functions but have different anatomical structures and evolutionary origins. The wings of a bird (modified forelimbs with bones and feathers) and the wings of an insect (membranous extensions of the exoskeleton) both evolved for flight but are not derived from a common winged ancestor. This is an example of convergent evolution.

Explanation:
The nucleus is bounded by a double membrane called the nuclear envelope, not a single membrane. It houses the nucleolus, which is the site of ribosomal RNA synthesis. The nuclear envelope is perforated by nuclear pores that regulate the bidirectional transport of molecules, including the export of mRNA to the cytoplasm. Thus, statements 2 and 3 are correct.

Explanation:
Ecological succession is the gradual and predictable process of change in the species composition of an ecological community over time. It occurs after a disturbance (secondary succession) or on a newly formed, lifeless substrate (primary succession). The final, stable community that is in near equilibrium with the environment is called the climax community. The entire sequence of communities is called a sere.