An atomic number of an element tells you the number of protons in every atom of that element. The number of protons is generally the same as the number of electrons too.
The mass number is the number of protons and neutrons combined.
Answer and Explanation:
Tracheophyte plants, also known as vascular plants, are those that possess a supportive tissue that can also conduct fluids -The Xileme- and another tissue that conducts nutritious elements produced by photosynthesis -The Phloem-. These plants have a root (basically underground), a stem (aerial), and leaves. All of them together form the corm. And the corm counts with these vascular tissues to which we referred before.
There are different types of Tracheophyte plants, some of them produce seeds to reproduce and disperse -Spermatophyta- and some others reproduce and disperse by spores -Pteridophyta-. This last seedless group corresponds to ferns and other similar plants.
Pteridophytes characterizes for having a sporophyte that has stems with leaves and a root. It also has primitive xylem composed by tracheids and phloem, both of them formed by vascular bundles located in a central cylinder.
Spores are its dispersion units and are responsible for colonizing new areas. They also constitute the resistance units under extremely unfavorable conditions.
Their life cycle is composed of the asexual phase (sporophytic phase) and the sexual phase (gametophytic).
- The <u>sporophyte</u>, the dominant asexual generation, it is a perennial and diploid structure. Its aerial part might disappear during unfavorable seasons, but it reappears during spring or summer. The sporophyte is in charge of asexual reproduction
- The<u> gametophyte</u>, instead, is and haploid structure, ephemeral and must be in the water for its survival, and for sexual reproduction to be successful. In the presence of water, masculine gametophyte -antherozoids- are released and they swim to the archegonium to meet the ovocell. Antherozoids can swim because they have flagella. After fertilization, a new sporophyte is produced.
The correct option is this: TWO DRAGONFLY SPECIES REGULARLY MATE BUT THEIR GAMETES ARE INCOMPATIBLE.
In biology, there are different types of reproductive barriers, one of these is prezygotic barrier. A prezygotic barrier is a kind of mechanism that prevent reproduction from occurring by blocking fertilization. In this case, the concerned species will be mating together, but their gametes will not be compatible and thus, zygote will not be formed.
A postzygotic barrier on the other hand is said to occur when the reproduction process is blocked after the formation of zygote or after fertilization has taken place. A good example of this is an hybrid mule that is sterile and can not reproduce.
Answer:
gallbladder
Explanation:
Bile is used to digest food and is stored in the gallbladder.
Answer:
It greatly affect population of fish.
Explanation:
If there were no shrimp in the close ecosystem then many fishes die due to lack f food because shrimp is the food of many small and large fishes. They also play a great role in protection of fish's skin by eating parasite, bacteria and fungi present on their skin so it also act as scavengers so if these shrimps are not present many fishes die due to various diseases and the ecosystem would be disturb.
