Answer:
They evolved after the seedless vascular plants.
Explanation:
- The gymnosperms were the first seed plants to have evolved some about 382.7 million to 358.9 million years ago in the Devonian period.
- They were the ancestor of the seed plants like the heterosporous, earlier gymnosperms were pteridosperms or seed ferns. The vascular plant's particular ferns consist of tissues that don't make flowers or seeds but have unicellular pores.
Answer:
Damian
Explanation:
The Doppler Effect is hard for me to put into words, but a common example is that when you stand still on the side of the road, you notice how the pitch of a fire engine's siren changes from when it's coming towards you vs driving away.
Explanation:
cells have proteins called receptors that bind to signaling molecules and initially I ate a physiological response...because membrane receptors interact with both exteacellar signals molecules within the cell, they permit signaling molecules to affect cell function without actually entering the cell.
Answer:
The sodium channel have refractory period.
Explanation:
Action potential are generated at axon hillock of neuron and travel across the neuron in response to stimuli. For the the generation of action potential the steps are stimulus, depolarization, repolarization, hyperpolarization and resting state.
So the first step for action potential after stimulus is depolarization. Depolarization requires the opening of sodium channels to make the inside of neuronal membrane positive. These sodium channels have refractory period. They cannot open immediately after activation. So the sodium channels of one direction in neuron (upstream) become refractory and it is convenent to open the sodium channels of other direction (downstream) of neuron. That why action potential is transmitted in one direction.
It is like the gunpowder placed at a line the fire cannot go back in burnt gun powder direction.
Answer:
The correct answer is - mitotic division or mitosis.
Explanation:
GMOs or genetically modified organisms are organisms, plants, animals whose DNA or genes are altered with the help of genetic engineers. In this case, transgenic tomatoes that are insect resistant, are produced to reduce the cost spend on using pesticides.
These altered genes transfer in the bacterium that reproduces in and passing the gene for insect resistance in a leaf cell onto the cells that develop from it.