Few fossils of the earliest animals still exist because they

Biology

1 answer:

vazorg [7]3 years ago

6 0

C is probably the best answer choice: Were soft bodied and tiny, therefore unlikely to fossilize.

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How would you expect the stomata of a leaf respond to a drought

VARVARA [1.3K]

The amount of stomata would decrease in response to drought
This is because the stomata are the principal means of gas exchange in the plants. This controls water loss and the exchange of CO2 and Oxygen.
In drought conditions, excessive evaporation might lead to desiccation and an equally severe disruption of photosynthetic function. Thus, one might expect plant leaves exposed to drought conditions to have fewer stomata in sunlit environments.

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3 years ago

Which of the following results when a sperm cell fertilizes an egg cell?

ExtremeBDS [4]

The answer is D. Zygote. A zygote is formed by the fertilization of an egg by a sperm. A gamete is what we refer to an egg or sperm as. Fertilization is what we call when a sperm and an egg come together, but it is not the product of the two.

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2 years ago

What is embryogenesis???

zmey [24]

Answer:

Embryogenesis is the development of an animal or plant embryo.

Embryogenesis is the process of development of an embryo from zygote. In embryogenesis, the zygote undergoes repeated cell division through mitosis. The divisions help in the growth of an embryo. Cells undergo differentiation attaining specific shape, size and function. Cell differentiation occurs at specific location resulting in the production of different tissue, organs and organ system.

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2 years ago

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Natural selection changes allele frequencies in populations because some ____ survive and reproduce more successfully than other

Mazyrski [523]

The correct answer is individuals
I hope this help

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2 years ago

DESCRIBE the internal anatomy of skeletal muscle, using each of the following terms: ACTIN, MYOSIN, THIN FILAMENT, THICK FILAMEN

jasenka [17]

INTERNAL ANATOMY OF SKELETAL MUSCLE : SKELETAL MUSCLE IS OTHERWISE CALLED AS STRIATED OR VOLUNTARY MUSCLE. THEIR ACTIVITIES ARE UNDER THE VOLUNTARY CONTROL OF NERVOUS SYSTEM. THEREFORE, THEY ARE KNOWN AS VOLUNTARY MUSCLES. PRIMARY FUNCTION OF THIS MUSCLE IS LOCOMOTION AND CHANGES IN BODY POSTURE.

EACH MUSCLE IS MADE UP OF NUMBER OF MUSCLE BUNDLES OR FASCICLES. THESE FASCICLES ARE HELD TOGETHER BY A COMMON COLLAGENOUS CONNECTIVE TISSUE LAYER CALLED FASCIA.

EACH MUSCLE IS COMPOSED OF NUMEROUS MUSCLE FIBRES AND IT IS MULTINUCLEATED, CROSS STRIATED CYLINDRICAL CELLS. IT IS MADE UP OF SARCOLEMMA OR CELL MEMBRANE ENCLOSING SARCOPLASM (CYTOPLASM) . NUMBER OF EVENLY DISTRIBUTED LONGITUDINAL THREADS CALLED MYOFIBRILS ARE PRESENT IN THE SARCOPLASM.

MUSCLE-FASCICULE-FIBRE-MYOFIBRILS-MYOFILAMENTS

EACH MUSCLE IS AN INDIVIDUAL CELL AND CONSISTS OF FOLLOWING PARTS.

SARCOLEMMA, SARCOPLASM, NUCLEI, MYOFIBRILS, MYOFILAMENTS, MITOCHONDRIA, SARCOPLASMIC RETICULUM.

SARCOLEMMA IS CELL MEMBRANE OF MUSCLE FIBRES AND SARCOPLASM IS SEMIFLUID CYTOPLASM OF MUSCLE.

NUCLEI ARE MULTIPLE IN NUMBER AND OVAL IN SHAPE, PERIPHERAL IN DISTRIBUTION BENEATH THE SARCOLEMMA.

MYOFIBRILS ARE CONTRACTILE UNBRANCHED THREADS SITUATED ALONG THE MUSCLE FIBRE. IT CONSIST OF ALTERNATE A-BAND

AND I-BAND. EACH MYOFIBRILS CONSISTS OF LONGITUDINALLY ARRANGED PROTEIN FILAMENTS SUCH AS THIN FILAMENT CONSISTS OF ACTIN, TROPOMYOSIN, TROPONIN WHEREAS THICK FILAMENT CONSISTS OF MYOSIN . THESE ARE CALLED MYOFILAMENTS.

MITOCHONDRIA PROVIDES ENERGY FOR THE WORK OF MUSCLE FIBRE.

BESIDES THE ABOVE COMPONENTS THERE ARE THREE TYPES OF SUPPORTING TISSUES WHICH HELPS IN ORGANIZATION OF SKELETAL MUSCLES. THESE ARE.

ENDOMYSIUM : IT IS A DELICATE SHEATH OF CONNECTIVE TISSUE WHICH COVERS EACH MUSCLE FIBRE OUTSIDE THE SARCOLEMMA.

PERIMYSIUM : THE MUSCLE FIBRES ARE GROUPED INTO FASCICULI EACH FASCICULUS IS COVERED BY A CONNECTIVE TISSUE SHEATH CALLED PERIMYSIUM.

EPIMYSIUM : THE ENTIRE MUSCLE IS COVERED BY A SHEATH OF CONNECTIVE TISSUE KNOWN AS THE EPIMYSIUM.

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2 years ago