Answer:
In bryophytes, the sporophyte is minute and dependent on the relatively prominent and nutritionally independent gametophyte for resources. The moss gametophyte looks like a miniature herb, with tiny leaf-like photosynthetic organs. The gametophyte generation begins as a dormant spore, which germinates under appropriate conditions to produce filamentous and branching protonemal tissues. These form multicellular bud-like structures, each of which develops into a leafy shoot. The mature gametophytes produce male and female sexual organs, the antheridia and archegonia, respectively. The gametophyte is often sexually distinct, and plants are either male or female.
Each antheridium has an outer layer that encloses and protects thousands of motile sperm, which swim through available external water layer to the egg. Fertilization at the base of the cylindrical archegonium produces a diploid zygote which develops into an unbranched sporophyte. The sporophyte consists of a thin stalk attached to the gametophyte, and a capsule that encloses the sporophytic meiotic cells.
In recent years, the mosses Physcomitrella patens and Funaria hygrometrica have emerged as attractive model systems for studying gene function in non-vascular plants because of the relative ease of molecular manipulation by homologous recombination. Mutants affecting gametophyte development have been isolated and their analysis should provide insights into the molecular basis of gametophyte development in mosses.
Explanation:
Explanation:
A rock would experience a temperature of 5500°C is about the core which is at a depth of 220km.
But let us use the earth's geothermal gradient to solve this problem.
The geothermal gradient is the rate at which temperature is increasing with depth.
The geothermal gradient 25°C/km
At 5500°C,
5500°C x
= 220km
But this is not so in nature, there are other heat sources that contributes to increasing temperature with depth such as radioactive heat and frictional heat.
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Answer:
A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the sun, Earth and moon are aligned (in "syzygy") exactly, or very closely so, with the Earth in the middle.
Explanation:
Because it's vital to the survival of all species, not just human, that we have resources such as food and water. Also that those resources be clean and healthy. We also need to manage resources such as oil to make sure there are fewer wars like the ones happening in the Middle East. If you need anything else just message me.