Answer:
C. <em>Clostridium</em> and <em>Bacillus</em>.
Explanation:
<em>Bacillus </em>and <em>Clostridium</em> are the gram-positive bacteria and form endospores. Endospores are the resistant dormant structures formed by some gram-positive bacteria.
These bacteria form the endospores within their vegetative cells. The endospores are highly resistant to environmental stress conditions and make these bacterial genera the dangerous pathogens.
Answer:
Humus (hummus) is a dark organic matter in the soil which is produced by the decay of leaves or twigs (leaf litter). The litter is decayed in the soil by the action of microbial communities and chemcial reactions (together called as biogeochemical reactions). This process is also known as decomposition. The higher humus content in the soil makes it more fertile because there are more nutrients releasing due to increased turnover of the decomposing bacteria. Further, humus formation is increased if more water (moisture content) and oxygen is available.
