The spider has a venom in their teeth that they inject into your skin when they bite you so you won’t bleed everywhere and your skin has a reaction to the venom because it’s strong enough to have an effect just not strong enough to hurt you.
Answer:
Topsoils are dark primarily because they contain dead organic material in various stages of decomposition. ... The degradation of organic matter within the soil produces a substance called humus, which has a complex chemical structure and is composed of carbon-rich compounds that impart the dark color.
Explanation:
When the organism become bipedal, they walk with 2 legs so there are 2 arms that were unused. Some of them try to use that hand by grabbing stick or stone, leading to tools. They start to think more to develop tools and their brain capacity become increased.
The ability to use stone tools will help in food digestion since it can break the food easier. This reduces the needs for bigger teeth/jaw.
Meiosis in bryophytes:
in bryophytes meiosis occur during formation of spores in sporophytic generation.
in gametophytic generation gametes formation occurs due to mitosis not with meiosis.