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Andre45 [30]
3 years ago
7

Sperm can be carried by _____ grains. ANSWERSSSSSSSSSSSSSSSSS O spore O stamen O pollen

Chemistry
2 answers:
Mama L [17]3 years ago
8 0

Answer:

pollen

Explanation:

you insolent vacuum

7nadin3 [17]3 years ago
4 0

What is pollen in the reproduction cycle of flowering plants?

A pollen grain is a microspore containing the male gametophyte, usually reduced to two undivided cells, each with one haploid (n) nucleus. These cells are surrounded by a very resistant wall, the exine, which generally has apertures, zones with less resistance which will allow the germination of the pollen tube.

Explanation of the reproduction cycle (cf diagram above)

A given species produces flowers bearing stamens. According to species, these flowers can be unisexual (stamens only) or bisexual (stamens and carpels).

The stamen anthers include 4 pollen sacs containing sporogenous cells (diploid=2n). These sporogenous cells undergo meiosis, each producing 4 microspores (haploid=n). Two nuclei are then formed by mitosis : the vegetative nucleus and the generative nucleus. The latter divides to form 2 sperms. Simultaneously the wall of the microspores becomes thicker and takes the characteristic shape of the species : it is a pollen grain (see: What are the morphological characteristics of pollen and spore grains?). In the majority of species, the 4 grains (resulting from the 4 microspores) split up into single grains; in some cases, they remain together (tetrad = group of 4 grains). When mature, pollen grains are released by the opening of the anthers.

A pollen grain is aimed at reaching another flower of the same species, bearing carpels. The ovaries contain ovules, in which meiosis occurs, then mitoses. It results in an embryo sac with 8 nuclei, among which an egg cell and 2 central cells. When a pollen grain arrives on another flower (see : How are the spores and pollen grains transported?), it is received by the stigmas.

The pollen grain germinates through an opening of the wall: the vegetative nucleus develops into a pollen tube which is guided by the style to the ovary, then enters the micropyle of an ovule. The pollen tube releases 2 sperm nuclei into the ovule: one of the sperms fuses with the egg cell into a zygote (2n), while the other sperm fuses with central nuclei and gives rise to albumen (= food source). There are generally several ovules in an ovary : each one can be fertilized by a distinct pollen grain.

Each fertilized ovule and its albumen form a seed that will develop into a new individual of this species. hope it works

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3 years ago
What is diffusion? How does the motion of gas molecules explain how a gas diffuses throughout a room?
Lady bird [3.3K]

Answer:

Diffusion in gases

Diffusion is driven by differences in concentration. When chemical substances such as perfume are let loose in a room, their particles mix with the particles of air. The particles of smelly gas are free to move quickly in all directions

Explanation:

hope this helps

5 0
3 years ago
Please help me with this question
vlada-n [284]
The answer to that question is B
7 0
2 years ago
Include two kinds
MatroZZZ [7]

Answer:

Explanation:

Ionic bond:

It is the bond which is formed by the transfer of electron from one atom to the atom of another element.  

Both bonded atoms have very large electronegativity difference. The atom with large electronegativity value accept the electron from other with smaller value of electronegativity.

For example:

Sodium chloride is ionic compound. The electronegativity of chlorine is 3.16 and for sodium is 0.93. There is large difference is present. That's why electron from sodium is transfer to the chlorine. Sodium becomes positive and chlorine becomes negative ion.  Both atoms are joint together by electrostatic interaction and ionic compound sodium chloride is formed.

Covalent bond:

It is formed by the sharing of electron pair between bonded atoms.  

The atom with larger electronegativity attract the electron pair more towards it self and becomes partial negative while the other atom becomes partial positive.

For example:

In water the electronegativity of oxygen is 3.44 and hydrogen is 2.2. That's why electron pair attracted more towards oxygen, thus oxygen becomes partial negative and hydrogen becomes partial positive and both bonded atoms connected together through covalent bond.

8 0
3 years ago
a mass of mercury occupies 0.350 l. what volume would an equal mass of ethanol occupy? the density of mercury is 13.546 g/ml and
Fed [463]

The density told you the mass covered by one unit of volume of that substance.

Density defines how perfectly the molecules of a substance are packed in a unit of volume.

In the given problem the substances are expressed in g/ml which means that a unit of volume will be 1 mL.

Given ,

Density of mercury = 13.546 g/ml

It means 1mL of mercury will have a mass of 13.546 g, Similarly 1 mL of ethanol will have a mass of 0.789 g.

0.350 L * 10^3 ml/1 L* 13.546/1 mL = 4,741.1 g

The volume of ethanol will have an equal mass is

4741.1 g* 1 mL/0.789g = 6,008.9 mL

6,008.9 mL* 1L/10^3mL = 6.0081 L

Hence the answer is 6.0081 L

To know more about density occupies here :

brainly.com/question/18518241?referrer=searchResults

#SPJ4

8 0
1 year ago
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