The answer is D, Because dinosaurs appears in the Triassic period while insects appeared in the Devonian period which is about 160 million years about, which rules out A and B. Humans have been on Earth for almost 3 million years, which is nothing compared to the history of life in earth, which about 4,000 million years of life history, so D
Steroid hormone
- The cell signaling pathways induced by the steroid hormones regulate specific genes within the cell's DNA. The hormones and receptor complex act as transcription regulators by increasing or decreasing the synthesis of mRNA molecules from specific genes.
- Steroid hormones are not able to target every cell within the body, so the overall response is slower. They bind to receptors on the cell's surface and the receptors aid in helping the steroid hormones enter the cell.
- Hormones work by binding to protein receptors either inside target cells or on their plasma membranes. The binding of a steroid hormone forms a hormone-receptor complex that affects gene expression in the nucleus of the target cell.
- Steroids pass into a cell's nucleus, bind to specific receptors and genes and trigger the cell to make proteins.
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brainly.com/question/10083019
It’s symmetrical if it’s equal on both sides?
Answer:
a. The letters Na with one dot
Explanation:
An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such determines or defines the structure of a chemical element.
Generally, atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.
In Chemistry, electrons can be defined as subatomic particles that are negatively charged and as such has a magnitude of -1.
Valency can be defined as a measure of the combining power of a chemical element with other atoms to form a molecule or chemical compound.
Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Thus, valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others.
Sodium is a chemical element that is found in group (1) of the periodic table and as such it has 1 electrons in its outermost shell. Also, the chemical symbol for Sodium is Na and it has one (1) valence electron.
A Lewis structure can be defined as a structural representation of an atom or molecule by using a dot to show the position and distribution of electron(s) around the atom or molecule.
Hence, the letters Na with one (1) dot is a correct Lewis structure diagram for Sodium (Na) because it has just one (1) valence electron in outermost shell.
For example, the Lewis structure diagram for Sodium (Na) is •Na.
