What are placoderms?

Answers

Answer 1

Answer: an extinct fish of the Devonian period, having the front part of the body encased in broad flat bony plates.

Answer 2

Answer: An extinct class of prehistoric, armoured fish.

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Which statement correctly explains the polarity of the water molecule?A.The hydrogen end of the molecule has a partial negative charge and the oxygen end has a partial positive charge.

B.The oxygen end of the molecule has a partial negative charge and the hydrogen end has a partial positive charge.

C.Both ends of the molecule have a partial negative charge, which attracts the other water molecule towards itself.

Answers

The oxygen end of the molecule has a partial negative charge and the hydrogen end has a partial positive charge. This is because of the electronegativities of the atoms O and H. O is more electronegative than H so electrons are more often around the O atom. Electrons are negatively charged, so this causes the partial negative charge on the O atom, similarly, the "deficiency" of electrons around the H atoms cause partial positive charges because the nuclear charge (protons) isn't balanced to the number of electrons around it.

Hope this helps :)

Secretes hormones that are stored in the posterior pituitary gland

Answers

Answer:

Hypothalamus

Explanation:

The cell bodies of the neurosecretory cells of the paraventricular and the supraoptic nuclei of the hypothalamus synthesize the hormones oxytocin and antidiuretic hormone (ADH), also called vasopressin. These hormones are stored and released in blood by the posterior pituitary gland. The posterior pituitary does not synthesize hormones.

The hormones from the hypothalamus are packed into vesicles and are transported to the axon terminals of the posterior pituitary via the hypothalamic–hypophyseal tract. The hormones are stored in axon terminals and released in the blood when required.

Which one of the following steps would be included in the primary response in humoral immunity?A. Antigen binds to antibodies
B. Cytotoxic T cells bind to infected body cells and destroy them
C. Helper T cells activate cytotoxic T cells
D. A macrophage consumes a virus and displays antigens on its surface and signals helper T cells to divide.

Answers

The answer is letter A.

Humoral immunity is a situation in which antigen binds to antibodies. It is also called as the anitbody-mediated beta cellularis immune system that is found in the extracellular fluids (e.g. antibodies, complement proteins, antimicrobial peptides. Humoral immunity is mediated by macromolecules and is so named because it can be found in the humours or body fluids.

_______ are more adapted for moist environments.

Answers

Answer:

Bryophytes

Explanation:

Bryophytes are small plants, usually a few inches tall, that preferentially live in moist, humid and shady places due to the absence of nutrient-carrying vessels.

Due to the absence of nutrient-carrying vessels in the bryophytes, water is absorbed from the environment and is transported in these plants from cell to cell throughout the body of the plant. This type of transport is relatively slow and limits the development of large plants. For this reason, bryophytes are always small, short.

Biology states that one thing is certain: if the terrestrial plant has no conductive vessels, it will be small and live in preferably moist and shady environments, for adaptive reasons.

Bryophytes are more adapted for moist environments. This is due to the fact that they can live in water-filled places with mild temperatures.

How many planes of symettry can you draw through a jelly fish?A-None
B-2-5
C-1
D-More than 5

Answers

I believe that the answer is B.) 2 - 5.

My reason being is because symmetry basically means 3-D , So you are asking how many sides can you see when looking through a jelly fish.

When looking through any jelly fish you will see 2-5 sides , 2-5 because there are four ( 4 ) , There is the front , the back and also both sides so it's four ( 4 ).

That was my reason for the answer I chose.

It would be D but you will not see at lease 5 sides to a jelly fish , why? = because they don't have 5 sides , most of them are square shaped or circular.

I really hope that this helped you out a lot.

Which of the following is not an abiotic limiting factor?Temperature

Water

Soil type

Organisms

Answers

the better answer is organism

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