When an atom of lithium loses an electron the atom becomes a

Sedimentary rocks form

grin007 [14]

Hello there!

Sedimentary rocks are formed due to layers so the answer is A.

Best wishes
-HuronGirl

5 0

3 years ago

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

7nadin3 [17]

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

4 0

3 years ago

Read 2 more answers

Which state of matter has a constant volume, but changes shape?\?

never [62]

Liquids stays the same volume but the bonds are spaced out enough that it can take the shape of whatever container it’s in.

8 0

3 years ago

Using only the periodic table, determine the element that displays each given trend. Be sure to provide your reasoning.

RideAnS [48]

Choose the element that:

- is more reactive: oxygen or argon.

- has the larger atomic radius: francium or sodium.

- has the smaller atomic radius: scandium or selenium.

- has more ionization energy: bismuth or mercury.

- has less ionization energy: nitrogen or phosphorus.

- has more electronegativity: xenon or silver.

- has less electronegativity: titanium or hafnium.

Explanation:

Choose the element that is more reactive: oxygen or argon.

Argon have a complete electronic shell which makes him inert from chemically point of view while oxygen is able to form compounds with the majority of the elements.

Choose the element that has the larger atomic radius: francium or sodium.

As you go down in a group the atomic radius is increasing.

Choose the element that has the smaller atomic radius: scandium or selenium.

As a general trend the atomic radius of elements decrease in periods from right to left for this elements .

Choose the element that has more ionization energy: bismuth or mercury.

Mercury have a complete electronic shell (5d¹⁰) while bismuth have 3 electrons in the last shell (6p³). It is harder to extract an electron from mercury compared to bismuth.

Choose the element that has less ionization energy: nitrogen or phosphorus.

Ionization energy decrease as you go down in a group.

Choose the element that has more electronegativity: xenon or silver.

Silver have a higher electronegativity than Xenon. Xenon is an inert gas and it has a complete electronic shell which explains his inert chemical reactivity.

Choose the element that has less electronegativity: titanium or hafnium.

As you go down a grup electronegativity is decreasing.

Learn more about:

trends in periodic table:

brainly.com/question/2293240

brainly.com/question/4433739

brainly.com/question/3266672

#learnwithBrainly

3 0

3 years ago

2 H2 (g) + O2 (g) --> 2 H2O (l)

goblinko [34]